diff --git a/Changelog.txt b/Changelog.txt
index ba2bd2818a..a891eff46b 100644
--- a/Changelog.txt
+++ b/Changelog.txt
@@ -496,7 +496,7 @@
 
 :: improved recipes
 - Jot Down
-- Various Russian and Ukranian news sources
+- Various Russian and Ukrainian news sources
 - Nautilus Magazine
 - Süddeutsche Zeitung
 - The India Forum
@@ -974,7 +974,7 @@
 
 - Fix a regression in 7.0 caused by a regression in Qt that would result in calibre hanging rarely when using the cover browser view
 
-- [2049992] Fix custom template functions not useable in save to disk templates
+- [2049992] Fix custom template functions not usable in save to disk templates
 
 - Fix a regression in 7.2 that caused the popup used for editing fields in the book list to be mis-positioned on very wide monitors
 
diff --git a/bypy/linux/__main__.py b/bypy/linux/__main__.py
index 12ab7b1c95..df88bd3c6e 100644
--- a/bypy/linux/__main__.py
+++ b/bypy/linux/__main__.py
@@ -55,10 +55,10 @@ def binary_includes():
             get_dll_path('bz2', 2), j(PREFIX, 'lib', 'libunrar.so'),
             get_dll_path('python' + py_ver, 2), get_dll_path('jbig', 2),
 
-            # We dont include libstdc++.so as the OpenGL dlls on the target
+            # We don't include libstdc++.so as the OpenGL dlls on the target
             # computer fail to load in the QPA xcb plugin if they were compiled
             # with a newer version of gcc than the one on the build computer.
-            # libstdc++, like glibc is forward compatible and I dont think any
+            # libstdc++, like glibc is forward compatible and I don't think any
             # distros do not have libstdc++.so.6, so it should be safe to leave it out.
             # https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html (The current
             # debian stable libstdc++ is  libstdc++.so.6.0.17)
diff --git a/bypy/macos/sign.py b/bypy/macos/sign.py
index 87279d74c1..fb1da2b95b 100644
--- a/bypy/macos/sign.py
+++ b/bypy/macos/sign.py
@@ -13,10 +13,10 @@ entitlements = {
     # MAP_JIT is used by libpcre which is bundled with Qt
     'com.apple.security.cs.allow-jit': True,
 
-    # v8 and therefore WebEngine need this as they dont use MAP_JIT
+    # v8 and therefore WebEngine need this as they don't use MAP_JIT
     'com.apple.security.cs.allow-unsigned-executable-memory': True,
 
-    # calibre itself does not use DYLD env vars, but dont know about its
+    # calibre itself does not use DYLD env vars, but don't know about its
     # dependencies.
     'com.apple.security.cs.allow-dyld-environment-variables': True,
 
diff --git a/bypy/windows/file_dialogs.cpp b/bypy/windows/file_dialogs.cpp
index 0d200710be..fea720eb8d 100644
--- a/bypy/windows/file_dialogs.cpp
+++ b/bypy/windows/file_dialogs.cpp
@@ -346,7 +346,7 @@ int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine
         return write_bytes(pipe, echo_sz, echo_buf) ? 0 : 1;
     }
 	if (app_uid != NULL) {
-        // dont check return status as failure is not critical
+        // don't check return status as failure is not critical
         set_app_uid(app_uid);
     }
 
diff --git a/bypy/windows/wix-template.xml b/bypy/windows/wix-template.xml
index 901a054b0a..b067f09ec8 100644
--- a/bypy/windows/wix-template.xml
+++ b/bypy/windows/wix-template.xml
@@ -5,16 +5,16 @@
     <SummaryInformation Keywords="Installer" Description="{app} Installer" Manufacturer="Kovid Goyal" />
 
     <!-- Disable creation of system restore points on calibre installs. Speeds
-         up the install. We dont need system restore since we dont install any
+         up the install. We don't need system restore since we don't install any
          system DLLs/components anyway (apart from start menu entries) -->
     <Property Id="MSIFASTINSTALL" Value="3" />
 
     <Media Id="1" Cabinet="{app}.cab" CompressionLevel="{compression}" EmbedCab="yes" />
     <!-- The following line ensures that DLLs are replaced even if
-        their version is the same as before or they dont have versions.
+        their version is the same as before or they don't have versions.
         Microsoft's brain dead installer will otherwise use file dates to
         determine whether to install a file or not. Simply not robust. And
-        since we dont install any system files whatsoever, we can never replace
+        since we don't install any system files whatsoever, we can never replace
         a system file with an older version. This way the calibre install
         should always result in a consistent set of files being present in the
         installation folder, though of course, with Microsoft there are no
diff --git a/format_docs/compression/zip.txt b/format_docs/compression/zip.txt
index 1565e775ba..a08202f1e0 100644
--- a/format_docs/compression/zip.txt
+++ b/format_docs/compression/zip.txt
@@ -402,7 +402,7 @@ V. General Format of a .ZIP file
          13 - Acorn Risc               14 - VFAT
          15 - alternate MVS            16 - BeOS
          17 - Tandem                   18 - OS/400
-         19 - OS/X (Darwin)            20 thru 255 - unused
+         19 - OS/X (Darwin)            20 through 255 - unused
 
           The lower byte indicates the ZIP specification version 
           (the version of this document) supported by the software 
@@ -719,7 +719,7 @@ V. General Format of a .ZIP file
           The Header ID field indicates the type of data that is in
           the following data block.
 
-          Header ID's of 0 thru 31 are reserved for use by PKWARE.
+          Header ID's of 0 through 31 are reserved for use by PKWARE.
           The remaining ID's can be used by third party vendors for
           proprietary usage.
 
@@ -1769,7 +1769,7 @@ Example:   0x02, 0x42, 0x01, 0x13
     This would generate the original bit length array of:
     (3, 3, 3, 3, 3, 2, 4, 4)
 
-    There are 8 codes in this table for the values 0 thru 7.  Using 
+    There are 8 codes in this table for the values 0 through 7.  Using 
     the algorithm to obtain the Shannon-Fano codes produces:
 
                                   Reversed     Order     Original
@@ -1909,8 +1909,8 @@ The bit lengths for the literal tables are sent first with the number
 of entries sent described by the 5 bits sent earlier.  There are up
 to 286 literal characters; the first 256 represent the respective 8
 bit character, code 256 represents the End-Of-Block code, the remaining
-29 codes represent copy lengths of 3 thru 258.  There are up to 30
-distance codes representing distances from 1 thru 32k as described
+29 codes represent copy lengths of 3 through 258.  There are up to 30
+distance codes representing distances from 1 through 32k as described
 below.
 
                              Length Codes
@@ -2221,7 +2221,7 @@ keys, based on random data, to render a plaintext attack on the
 data ineffective.
 
 Read the 12-byte encryption header into Buffer, in locations
-Buffer(0) thru Buffer(11).
+Buffer(0) through Buffer(11).
 
 loop for i <- 0 to 11
     C <- buffer(i) ^ decrypt_byte()
diff --git a/manual/plugin_examples/interface_demo/config.py b/manual/plugin_examples/interface_demo/config.py
index 53b3a6bbe4..8e820e26ed 100644
--- a/manual/plugin_examples/interface_demo/config.py
+++ b/manual/plugin_examples/interface_demo/config.py
@@ -14,7 +14,7 @@ from calibre.utils.config import JSONConfig
 # Remember that this name (i.e. plugins/interface_demo) is also
 # in a global namespace, so make it as unique as possible.
 # You should always prefix your config file name with plugins/,
-# so as to ensure you dont accidentally clobber a calibre config file
+# so as to ensure you don't accidentally clobber a calibre config file
 prefs = JSONConfig('plugins/interface_demo')
 
 # Set defaults
diff --git a/manual/plugin_examples/interface_demo/main.py b/manual/plugin_examples/interface_demo/main.py
index 5f58b06ec4..43b42f2b72 100644
--- a/manual/plugin_examples/interface_demo/main.py
+++ b/manual/plugin_examples/interface_demo/main.py
@@ -140,7 +140,7 @@ class DemoDialog(QDialog):
                 set_metadata(ffile, mi, fmt)
                 ffile.seek(0)
                 # Now replace the file in the calibre library with the updated
-                # file. We dont use add_format_with_hooks as the hooks were
+                # file. We don't use add_format_with_hooks as the hooks were
                 # already run when the file was first added to calibre.
                 db.add_format(book_id, fmt, ffile, run_hooks=False)
 
diff --git a/manual/plugin_examples/interface_demo/ui.py b/manual/plugin_examples/interface_demo/ui.py
index 68da594af9..29f393018a 100644
--- a/manual/plugin_examples/interface_demo/ui.py
+++ b/manual/plugin_examples/interface_demo/ui.py
@@ -22,7 +22,7 @@ class InterfacePlugin(InterfaceAction):
     name = 'Interface Plugin Demo'
 
     # Declare the main action associated with this plugin
-    # The keyboard shortcut can be None if you dont want to use a keyboard
+    # The keyboard shortcut can be None if you don't want to use a keyboard
     # shortcut. Remember that currently calibre has no central management for
     # keyboard shortcuts, so try to use an unusual/unused shortcut.
     action_spec = ('Interface Plugin Demo', None,
diff --git a/pyproject.toml b/pyproject.toml
index 0da1b81111..52a51de0c9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,6 +74,125 @@ docstring-quotes = 'single'
 inline-quotes = 'single'
 multiline-quotes = 'single'
 
+[tool.codespell]
+# calibre will probably never fully compliant with codespell
+# this setting is only to easily find common typo errors
+# by filtering a great range of false-positives, but not all
+# (if codespell could per-file-ignores words, its be nicer)
+count = false
+summary = false
+quiet-level = 3
+regex = '''\b(?<!&)(?<!&amp;)[\w\-']+(?!&(amp;)?)\b'''
+builtin = [
+    'clear',
+    'rare',
+    'informal',
+    'code',
+]
+ignore-words-list = [
+    "alo",
+    "ans",
+    "clen",
+    "eto",
+    "fo",
+    "nam",
+    "nd",
+    "som",
+    "te",
+    "atLeast",
+    "Implementor",
+    "implementor",
+    "Implementors",
+    "implementors",
+    "missings",
+    "re-use",
+    "re-used",
+    "re-using",
+    "succeded",
+    # code
+    "ws",
+    "ws",
+    "ws",
+    "ws",
+    "dur",
+    "ro",
+    "snd",
+    "ws",
+    "deque",
+    "assertIn",
+    "atEnd",
+    "endcode",
+    "errorString",
+    "FocusIn",
+    "iff",
+    "lets",
+    "lite",
+    "NMAKE",
+    "nmake",
+    "uDate",
+    "UINT",
+    "uInt",
+    "uint",
+    "KeyPair",
+    "Keypair",
+    "keypair",
+    "Referer",
+    "seeked",
+    "sinc",
+    "stdio",
+    "thead",
+]
+uri-ignore-words-list = '*'
+skip = [
+    "*.svg",
+    "*.rcc",
+    "*_ui.py",
+    "./src/calibre/ebooks/rtf2xml/char_set.py",
+    "./src/calibre/ebooks/unihandecode/*",
+    "./src/calibre/ebooks/html_entities.h",
+    "./src/calibre/ebooks/html_entities.py",
+    "./src/calibre/utils/icu_test.py",
+    "./src/calibre/utils/search_query_parser_test.py",
+    "./Changelog.old.txt",
+    "./COPYRIGHT",
+    "./LICENSE",
+    "./LICENSE.rtf",
+    "./session.vim",
+    "./build/*",
+    "./docs/*",
+    "./nbproject/*",
+    "./recipes/*",
+    "./translations/*",
+    "./tags/*",
+    "./manual/generated/*",
+    "./manual/locale/*",
+    "./resources/dictionaries/*",
+    "./resources/localization/*",
+    "./resources/hyphenation/*",
+    "./resources/mathjax/*",
+    "./resources/builtin_recipes.xml",
+    "./resources/changelog.json",
+    "./resources/editor.js",
+    "./resources/editor-functions.json",
+    "./resources/mime.types",
+    "./resources/piper-voices.json",
+    "./resources/stylelint-bundle.min.js",
+    "./resources/user-manual-translation-stats.json",
+    "./resources/template-functions.json",
+    "./resources/viewer.js",
+    "./resources/viewer.html",
+    "./resources/content-server/index-generated.html",
+    "./setup/installer/*",
+    "./setup/pyqt_enums/*",
+    "./setup/lc_data.py",
+    "./setup/linux-installer.py",
+    "./src/css_selectors/*",
+    "./src/polyglot/*",
+    "./src/templite/*",
+    "./src/tinycss/*",
+    "./src/unicode_names/*",
+]
+
 [tool.flynt]
 line-length = 400  # over value to catch every case
 transform-format = false  # don't transform already existing format call
diff --git a/recipes/baltimore_sun.recipe b/recipes/baltimore_sun.recipe
index 3138a720d9..3e68e57165 100644
--- a/recipes/baltimore_sun.recipe
+++ b/recipes/baltimore_sun.recipe
@@ -81,7 +81,7 @@ class BaltimoreSun(BasicNewsRecipe):
         (u'Maryland Weather', u'http://www.baltimoresun.com/news/weather/weather-blog/rss2.0.xml'),
         (u'Second Opinion', u'http://www.baltimoresun.com/news/opinion/second-opinion-blog/rss2.0.xml'),
         (u'Sun Investigates', u'http://www.baltimoresun.com/news/maryland/sun-investigates/rss2.0.xml'),
-        (u'You Dont Say', u'http://www.baltimoresun.com/news/language-blog/rss2.0.xml'),
+        (u"You Don't Say", u'http://www.baltimoresun.com/news/language-blog/rss2.0.xml'),
 
         # Business Blogs ##
         (u'BaltTech', u'http://www.baltimoresun.com/business/technology/blog/rss2.0.xml'),
diff --git a/recipes/epw_magazine.recipe b/recipes/epw_magazine.recipe
index ff258fbc16..9e258a08ed 100644
--- a/recipes/epw_magazine.recipe
+++ b/recipes/epw_magazine.recipe
@@ -45,7 +45,7 @@ class epw(BasicNewsRecipe):
                 '/styles/freeissue/public', ''
             )
         except Exception:
-            # sometimes they dont add img src
+            # sometimes they don't add img src
             self.cover_url = 'https://www.epw.in/sites/default/files/cache/cover_images/2022/Cover_4June2022_Big.gif'
 
         feeds = OrderedDict()
diff --git a/recipes/espn.recipe b/recipes/espn.recipe
index fa8f4df801..2944e9a22a 100644
--- a/recipes/espn.recipe
+++ b/recipes/espn.recipe
@@ -61,7 +61,7 @@ class ESPN(BasicNewsRecipe):
     def get_browser(self):
         br = BasicNewsRecipe.get_browser(self)
         if False and self.username and self.password:
-            # ESPN has changed to a JS based login system, cant be bothered
+            # ESPN has changed to a JS based login system, can't be bothered
             # revering it
             br.set_handle_refresh(False)
             url = ('https://r.espn.go.com/members/v3_1/login')
diff --git a/recipes/financial_times.recipe b/recipes/financial_times.recipe
index 6374f1076d..6322a54b37 100644
--- a/recipes/financial_times.recipe
+++ b/recipes/financial_times.recipe
@@ -71,7 +71,7 @@ class ft(BasicNewsRecipe):
     # def get_browser(self, *args, **kw):
     #     br = super().get_browser(*args, **kw)
     #     if self.username and self.password:
-    #         # ft.com uses a CAPTCHA on its login page so this sadly doesnt work
+    #         # ft.com uses a CAPTCHA on its login page so this sadly doesn't work
     #         br.open('https://accounts.ft.com/login?location=https%3A%2F%2Fwww.ft.com')
     #         br.select_form(id='email-form')
     #         br['email'] = self.username
diff --git a/recipes/independent_australia.recipe b/recipes/independent_australia.recipe
index f0968398dc..2873fecf42 100644
--- a/recipes/independent_australia.recipe
+++ b/recipes/independent_australia.recipe
@@ -77,7 +77,7 @@ class IndependentAustralia(BasicNewsRecipe):
         businessArticles = []
         lifeArticles = []
         australiaArticles = []
-        # Loop thru the articles in all feeds to find articles with base categories in it
+        # Loop through the articles in all feeds to find articles with base categories in it
         for curfeed in feeds:
             delList = []
             for a, curarticle in enumerate(curfeed.articles):
diff --git a/recipes/miami_herald.recipe b/recipes/miami_herald.recipe
index ed220abc3a..8570ae366b 100644
--- a/recipes/miami_herald.recipe
+++ b/recipes/miami_herald.recipe
@@ -56,7 +56,7 @@ class TheMiamiHerald(BasicNewsRecipe):
     ]
 
     def get_browser(self, *a, **kw):
-        # MyClatchy servers dont like the user-agent header, they hang forever
+        # MyClatchy servers don't like the user-agent header, they hang forever
         # when it is present
         br = BasicNewsRecipe.get_browser(self, *a, **kw)
         br.addheaders = [x for x in br.addheaders if x[0].lower() != 'user-agent']
diff --git a/recipes/satmagazine.recipe b/recipes/satmagazine.recipe
index c5388083dd..c49b3c3cf4 100644
--- a/recipes/satmagazine.recipe
+++ b/recipes/satmagazine.recipe
@@ -107,7 +107,7 @@ class SatMagazine(BasicNewsRecipe):
 
         title_number = 0
 
-        # Goes thru all the articles one by one and sort them out
+        # Goes through all the articles one by one and sort them out
         for article in articles:
 
             title = self.tag_to_string(article)
diff --git a/resources/pdf-preprint.js b/resources/pdf-preprint.js
index 384bdabb09..c2b2fa25b3 100644
--- a/resources/pdf-preprint.js
+++ b/resources/pdf-preprint.js
@@ -8,7 +8,7 @@
 
 (function() {
 "use strict";
-    // wrap up long words that dont fit in the page
+    // wrap up long words that don't fit in the page
     document.body.style.overflowWrap = 'break-word';
 
     var break_avoid_block_styles = {
diff --git a/resources/toc.js b/resources/toc.js
index 03e68baa1a..5c84e1928b 100644
--- a/resources/toc.js
+++ b/resources/toc.js
@@ -12,7 +12,7 @@
     var settings = SETTINGS;
 
     function onclick(event) {
-        // We dont want this event to trigger onclick on this element's parent
+        // We don't want this event to trigger onclick on this element's parent
         // block, if any.
         event.stopPropagation();
         var frac = window.pageYOffset/document.body.scrollHeight;
diff --git a/setup/build.py b/setup/build.py
index 44b3abf01f..3e9f3975cc 100644
--- a/setup/build.py
+++ b/setup/build.py
@@ -580,7 +580,7 @@ class Build(Command):
             if iswindows or env is self.windows_cross_env:
                 pre_ld_flags = []
                 if ext.uses_icu:
-                    # windows has its own ICU libs that dont work
+                    # windows has its own ICU libs that don't work
                     pre_ld_flags = elib
                 cmd += pre_ld_flags + env.ldflags + ext.ldflags + elib + xlib + \
                     ['/EXPORT:' + init_symbol_name(ext.name)] + all_objects + ['/OUT:'+dest]
@@ -623,7 +623,7 @@ class Build(Command):
     def build_headless(self):
         from setup.parallel_build import cpu_count
         if iswindows or ishaiku:
-            return  # Dont have headless operation on these platforms
+            return  # Don't have headless operation on these platforms
         from setup.build_environment import CMAKE, sw
         self.info('\n####### Building headless QPA plugin', '#'*7)
         a = absolutize
diff --git a/setup/installers.py b/setup/installers.py
index fa21a25605..a96b2a0d3e 100644
--- a/setup/installers.py
+++ b/setup/installers.py
@@ -57,7 +57,7 @@ def get_dist(base, which, bitness):
 
 def shutdown_allowed(which, bitness):
     # The ARM64 VM is extremely flakey often booting up to a non-functional
-    # state so dont shut it down as it seems to be more stable once bootup is
+    # state so don't shut it down as it seems to be more stable once boot-up is
     # done.
     return bitness != 'arm64'
 
diff --git a/setup/translations.py b/setup/translations.py
index 414f27cc23..c946b32c10 100644
--- a/setup/translations.py
+++ b/setup/translations.py
@@ -286,7 +286,7 @@ class Translations(POT):  # {{{
 
     def is_po_file_ok(self, x):
         bname = os.path.splitext(os.path.basename(x))[0]
-        # sr@latin.po is identical to sr.po. And we dont support country
+        # sr@latin.po is identical to sr.po. And we don't support country
         # specific variants except for a few.
         if '_' in bname:
             return bname.partition('_')[0] in ('pt', 'zh', 'bn')
diff --git a/src/calibre/customize/profiles.py b/src/calibre/customize/profiles.py
index ba285fbf27..3d6bcd9a07 100644
--- a/src/calibre/customize/profiles.py
+++ b/src/calibre/customize/profiles.py
@@ -45,7 +45,7 @@ class InputProfile(Plugin):
     type = _('Input profile')
 
     name        = 'Default Input Profile'
-    short_name  = 'default'  # Used in the CLI so dont use spaces etc. in it
+    short_name  = 'default'  # Used in the CLI so don't use spaces etc. in it
     description = _('This profile tries to provide sane defaults and is useful '
                     'if you know nothing about the input document.')
 
@@ -243,7 +243,7 @@ class OutputProfile(Plugin):
     type = _('Output profile')
 
     name        = 'Default Output Profile'
-    short_name  = 'default'  # Used in the CLI so dont use spaces etc. in it
+    short_name  = 'default'  # Used in the CLI so don't use spaces etc. in it
     description = _('This profile tries to provide sane defaults and is useful '
                     'if you want to produce a document intended to be read at a '
                     'computer or on a range of devices.')
diff --git a/src/calibre/customize/ui.py b/src/calibre/customize/ui.py
index 1011a7b903..6313da5e50 100644
--- a/src/calibre/customize/ui.py
+++ b/src/calibre/customize/ui.py
@@ -715,7 +715,7 @@ def patch_metadata_plugins(possibly_updated_plugins):
             if pup is not None:
                 if pup.version > plugin.version and pup.minimum_calibre_version <= numeric_version:
                     patches[i] = pup(None)
-                    # Metadata source plugins dont use initialize() but that
+                    # Metadata source plugins don't use initialize() but that
                     # might change in the future, so be safe.
                     patches[i].initialize()
     for i, pup in iteritems(patches):
diff --git a/src/calibre/db/backend.py b/src/calibre/db/backend.py
index 75fc8cb771..abbfbb02ec 100644
--- a/src/calibre/db/backend.py
+++ b/src/calibre/db/backend.py
@@ -2283,7 +2283,7 @@ class DB:
 
     def remove_trash_formats_dir_if_empty(self, book_id):
         bdir = os.path.join(self.trash_dir, 'f', str(book_id))
-        if os.path.isdir(bdir) and len(os.listdir(bdir)) <= 1:  # dont count metadata.json
+        if os.path.isdir(bdir) and len(os.listdir(bdir)) <= 1:  # don't count metadata.json
             self.rmtree(bdir)
 
     def list_trash_entries(self):
diff --git a/src/calibre/db/cache.py b/src/calibre/db/cache.py
index 083f573ea8..c8c772a5b8 100644
--- a/src/calibre/db/cache.py
+++ b/src/calibre/db/cache.py
@@ -373,7 +373,7 @@ class Cache:
             mi.format_metadata = FormatMetadata(self, book_id, formats)
             good_formats = FormatsList(sorted(formats), mi.format_metadata)
         # These three attributes are returned by the db2 get_metadata(),
-        # however, we dont actually use them anywhere other than templates, so
+        # however, we don't actually use them anywhere other than templates, so
         # they have been removed, to avoid unnecessary overhead. The templates
         # all use _proxy_metadata.
         # mi.book_size   = self._field_for('size', book_id, default_value=0)
@@ -3474,7 +3474,7 @@ class Cache:
                         self._add_extra_files(dest_id, {q: BytesIO(cdata)}, replace=False, auto_rename=True)
                         break
 
-        for key in self.field_metadata:  # loop thru all defined fields
+        for key in self.field_metadata:  # loop through all defined fields
             fm = self.field_metadata[key]
             if not fm['is_custom']:
                 continue
diff --git a/src/calibre/db/notes/connect.py b/src/calibre/db/notes/connect.py
index 97ac783cf7..1e8d7147bd 100644
--- a/src/calibre/db/notes/connect.py
+++ b/src/calibre/db/notes/connect.py
@@ -119,7 +119,7 @@ class Notes:
     def path_for_resource(self, resource_hash: str) -> str:
         hashalg, digest = resource_hash.split(':', 1)
         prefix = digest[:2]
-        # Cant use colons in filenames on windows safely
+        # Can't use colons in filenames on windows safely
         return os.path.join(self.resources_dir, prefix, f'{hashalg}-{digest}')
 
     def remove_resources(self, conn, note_id, resources_to_potentially_remove, delete_from_link_table=True):
diff --git a/src/calibre/db/restore.py b/src/calibre/db/restore.py
index c8d696ebff..0176e7da20 100644
--- a/src/calibre/db/restore.py
+++ b/src/calibre/db/restore.py
@@ -135,7 +135,7 @@ class Restore(Thread):
                 tdir = TemporaryDirectory('_rlib', dir=basedir)
                 tdir.__enter__()
             except OSError:
-                # In case we dont have permissions to create directories in the
+                # In case we don't have permissions to create directories in the
                 # parent folder of the src library
                 tdir = TemporaryDirectory('_rlib')
 
diff --git a/src/calibre/db/search.py b/src/calibre/db/search.py
index a6920cfa38..5603908b9e 100644
--- a/src/calibre/db/search.py
+++ b/src/calibre/db/search.py
@@ -707,7 +707,7 @@ class Parser(SearchQueryParser):  # {{{
                 continue
             if fm['search_terms'] and x not in {'series_sort', 'id'}:
                 if x not in self.virtual_fields and x != 'uuid':
-                    # We dont search virtual fields because if we do, search
+                    # We don't search virtual fields because if we do, search
                     # caching will not be used
                     all_locs.add(x)
                 field_metadata[x] = fm
diff --git a/src/calibre/db/tests/legacy.py b/src/calibre/db/tests/legacy.py
index d72db808c0..093fdf38b9 100644
--- a/src/calibre/db/tests/legacy.py
+++ b/src/calibre/db/tests/legacy.py
@@ -46,8 +46,8 @@ def get_defaults(spec):
 
 
 def compare_argspecs(old, new, attr):
-    # We dont compare the names of the non-keyword arguments as they are often
-    # different and they dont affect the usage of the API.
+    # We don't compare the names of the non-keyword arguments as they are often
+    # different and they don't affect the usage of the API.
 
     ok = len(old.args) == len(new.args) and get_defaults(old) == get_defaults(new)
     if not ok:
diff --git a/src/calibre/devices/__init__.py b/src/calibre/devices/__init__.py
index a328aad63f..c580923a21 100644
--- a/src/calibre/devices/__init__.py
+++ b/src/calibre/devices/__init__.py
@@ -188,7 +188,7 @@ def debug(ioreg_to_tmp=False, buf=None, plugins=None,
                 out(' ')
                 if ioreg_to_tmp:
                     open('/tmp/ioreg.txt', 'w').write(ioreg)
-                    out('Dont forget to send the contents of /tmp/ioreg.txt')
+                    out("Don't forget to send the contents of /tmp/ioreg.txt")
                     out('You can open it with the command: open /tmp/ioreg.txt')
                 else:
                     out(ioreg)
diff --git a/src/calibre/devices/mtp/unix/upstream/music-players.h b/src/calibre/devices/mtp/unix/upstream/music-players.h
index 1fe1a1fe58..dbe8adcf21 100644
--- a/src/calibre/devices/mtp/unix/upstream/music-players.h
+++ b/src/calibre/devices/mtp/unix/upstream/music-players.h
@@ -299,7 +299,7 @@
      DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST |
      DEVICE_FLAG_PLAYLIST_SPL_V1 },
   // YP-F3 is NOT MTP - USB mass storage
-  // From a rouge .INF file
+  // From a rogue .INF file
   // this device ID seems to have been recycled for:
   // the Samsung SGH-A707 Cingular cellphone
   // the Samsung L760-V cellphone
@@ -1183,7 +1183,7 @@
       DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST_ALL },
   // From: Willy Gardiol (web) <willy@gardiol.org>
   // Spurious errors for getting all objects, lead me to believe
-  // this flag atleast is needed
+  // this flag at least is needed
   { "Nokia", 0x0421, "5800 XpressMusic v2", 0x0155,
       DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST_ALL },
   // Yet another version... I think
diff --git a/src/calibre/devices/winusb.py b/src/calibre/devices/winusb.py
index b183aae199..ac0bda3deb 100644
--- a/src/calibre/devices/winusb.py
+++ b/src/calibre/devices/winusb.py
@@ -922,7 +922,7 @@ def get_usb_info(usbdev, debug=False):  # {{{
     try:
         buf, dd = get_device_descriptor(handle, device_port)
         if dd.idVendor == usbdev.vendor_id and dd.idProduct == usbdev.product_id and dd.bcdDevice == usbdev.bcd:
-            # Dont need to read language since we only care about english names
+            # Don't need to read language since we only care about english names
             # buf, langs = get_device_languages(handle, device_port)
             # print(111, langs)
             for index, name in ((dd.iManufacturer, 'manufacturer'), (dd.iProduct, 'product'), (dd.iSerialNumber, 'serial_number')):
diff --git a/src/calibre/ebooks/conversion/plugins/htmlz_input.py b/src/calibre/ebooks/conversion/plugins/htmlz_input.py
index 1a0df9cfcb..009aa68bfd 100644
--- a/src/calibre/ebooks/conversion/plugins/htmlz_input.py
+++ b/src/calibre/ebooks/conversion/plugins/htmlz_input.py
@@ -117,7 +117,7 @@ class HTMLZInput(InputFormatPlugin):
         if opf:
             opf_parsed = OPF(opf, basedir=os.getcwd())
             cover_path = opf_parsed.raster_cover or opf_parsed.cover
-            os.remove(opf)  # dont confuse code that searches for OPF files later on the oeb object will create its own OPF
+            os.remove(opf)  # don't confuse code that searches for OPF files later on the oeb object will create its own OPF
         # Set the cover.
         if cover_path:
             cdata = None
diff --git a/src/calibre/ebooks/docx/block_styles.py b/src/calibre/ebooks/docx/block_styles.py
index bf9910138f..a7372d3c3d 100644
--- a/src/calibre/ebooks/docx/block_styles.py
+++ b/src/calibre/ebooks/docx/block_styles.py
@@ -123,7 +123,7 @@ def read_single_border(parent, edge, XPath, get):
                 pass
         sz = get(elem, 'w:sz')
         if sz is not None:
-            # we dont care about art borders (they are only used for page borders)
+            # we don't care about art borders (they are only used for page borders)
             try:
                 width = min(96, max(2, float(sz))) / 8
             except (ValueError, TypeError):
diff --git a/src/calibre/ebooks/docx/char_styles.py b/src/calibre/ebooks/docx/char_styles.py
index abec7b9183..57d1d20008 100644
--- a/src/calibre/ebooks/docx/char_styles.py
+++ b/src/calibre/ebooks/docx/char_styles.py
@@ -33,7 +33,7 @@ def read_text_border(parent, dest, XPath, get):
                 pass
         sz = get(elem, 'w:sz')
         if sz is not None:
-            # we dont care about art borders (they are only used for page borders)
+            # we don't care about art borders (they are only used for page borders)
             try:
                 # A border of less than 1pt is not rendered by WebKit
                 border_width = min(96, max(8, float(sz))) / 8
diff --git a/src/calibre/ebooks/docx/writer/from_html.py b/src/calibre/ebooks/docx/writer/from_html.py
index 3e42631fa1..27e9f8d4cd 100644
--- a/src/calibre/ebooks/docx/writer/from_html.py
+++ b/src/calibre/ebooks/docx/writer/from_html.py
@@ -520,7 +520,7 @@ class Convert:
             if float_spec is None and is_float:
                 float_spec = FloatSpec(self.docx.namespace, html_tag, tag_style)
 
-            if display in {'inline', 'inline-block'} or tagname == 'br':  # <br> has display:block but we dont want to start a new paragraph
+            if display in {'inline', 'inline-block'} or tagname == 'br':  # <br> has display:block but we don't want to start a new paragraph
                 if is_float and float_spec.is_dropcaps:
                     self.add_block_tag(tagname, html_tag, tag_style, stylizer, float_spec=float_spec)
                     float_spec = None
@@ -539,7 +539,7 @@ class Convert:
                     self.blocks.start_new_table(html_tag, tag_style)
             else:
                 if tagname == 'img' and is_float:
-                    # Image is floating so dont start a new paragraph for it
+                    # Image is floating so don't start a new paragraph for it
                     self.add_inline_tag(tagname, html_tag, tag_style, stylizer)
                 else:
                     if tagname == 'hr':
diff --git a/src/calibre/ebooks/epub/cfi/parse.py b/src/calibre/ebooks/epub/cfi/parse.py
index a5e97e2174..09c99d4ff3 100644
--- a/src/calibre/ebooks/epub/cfi/parse.py
+++ b/src/calibre/ebooks/epub/cfi/parse.py
@@ -9,7 +9,7 @@ import regex
 
 class Parser:
     ''' See epubcfi.ebnf for the specification that this parser tries to
-    follow. I have implemented it manually, since I dont want to depend on
+    follow. I have implemented it manually, since I don't want to depend on
     grako, and the grammar is pretty simple. This parser is thread-safe, i.e.
     it can be used from multiple threads simultaneously. '''
 
diff --git a/src/calibre/ebooks/lit/reader.py b/src/calibre/ebooks/lit/reader.py
index f6df491afd..0216746240 100644
--- a/src/calibre/ebooks/lit/reader.py
+++ b/src/calibre/ebooks/lit/reader.py
@@ -580,7 +580,7 @@ class LitFile:
             offset, size = u32(piece), int32(piece[8:])
             piece = self.read_raw(offset, size)
             if i == 0:
-                continue  # Dont need this piece
+                continue  # Don't need this piece
             elif i == 1:
                 if u32(piece[8:])  != self.entry_chunklen or \
                    u32(piece[12:]) != self.entry_unknown:
diff --git a/src/calibre/ebooks/lrf/html/convert_from.py b/src/calibre/ebooks/lrf/html/convert_from.py
index eb9dedc579..228341bdba 100644
--- a/src/calibre/ebooks/lrf/html/convert_from.py
+++ b/src/calibre/ebooks/lrf/html/convert_from.py
@@ -814,7 +814,7 @@ class HTMLConverter:
 
         collapse_whitespace = 'white-space' not in css or css['white-space'] != 'pre'
         if self.process_alignment(css) and collapse_whitespace:
-            # Dont want leading blanks in a new paragraph
+            # Don't want leading blanks in a new paragraph
             src = src.lstrip()
 
         def append_text(src):
diff --git a/src/calibre/ebooks/mobi/debug/index.py b/src/calibre/ebooks/mobi/debug/index.py
index c122db4293..2ef2d8d416 100644
--- a/src/calibre/ebooks/mobi/debug/index.py
+++ b/src/calibre/ebooks/mobi/debug/index.py
@@ -51,7 +51,7 @@ def read_variable_len_data(data, header):
         header['tagx_block_size'] = 0
     trailing_bytes = data[idxt_offset+idxt_size:]
     if trailing_bytes.rstrip(b'\0'):
-        raise ValueError('Traling bytes after last IDXT entry: {!r}'.format(trailing_bytes.rstrip(b'\0')))
+        raise ValueError('Trailing bytes after last IDXT entry: {!r}'.format(trailing_bytes.rstrip(b'\0')))
     header['indices'] = indices
 
 
diff --git a/src/calibre/ebooks/mobi/debug/mobi6.py b/src/calibre/ebooks/mobi/debug/mobi6.py
index cd5cf871a1..7ea630cf18 100644
--- a/src/calibre/ebooks/mobi/debug/mobi6.py
+++ b/src/calibre/ebooks/mobi/debug/mobi6.py
@@ -637,11 +637,11 @@ class TBSIndexing:  # {{{
                 ai, extra, consumed = decode_tbs(byts)
                 byts = byts[consumed:]
                 if extra.get(0b0010, None) is not None:
-                    raise ValueError('Dont know how to interpret flag 0b0010'
+                    raise ValueError("Don't know how to interpret flag 0b0010"
                             ' while reading section transitions')
                 if extra.get(0b1000, None) is not None:
                     if len(extra) > 1:
-                        raise ValueError('Dont know how to interpret flags'
+                        raise ValueError("Don't know how to interpret flags"
                                 f' {extra!r} while reading section transitions')
                     nsi = self.get_index(psi.index+1)
                     ans.append(
@@ -675,7 +675,7 @@ class TBSIndexing:  # {{{
             si, extra, consumed = decode_tbs(byts)
             byts = byts[consumed:]
             if len(extra) > 1 or 0b0010 in extra or 0b1000 in extra:
-                raise ValueError(f'Dont know how to interpret flags {extra!r}'
+                raise ValueError(f"Don't know how to interpret flags {extra!r}"
                         ' when reading starting section')
             si = self.get_index(si)
             ans.append('The section at the start of this record is:'
diff --git a/src/calibre/ebooks/mobi/reader/index.py b/src/calibre/ebooks/mobi/reader/index.py
index f70ee76022..aade17312f 100644
--- a/src/calibre/ebooks/mobi/reader/index.py
+++ b/src/calibre/ebooks/mobi/reader/index.py
@@ -55,7 +55,7 @@ def parse_indx_header(data):
     ans['ordt_map'] = ''
 
     if ordt1 > 0 and data[ordt1:ordt1+4] == b'ORDT':
-        # I dont know what this is, but using it seems to be unnecessary, so
+        # I don't know what this is, but using it seems to be unnecessary, so
         # just leave it as the raw bytestring
         ans['ordt1_raw'] = data[ordt1+4:ordt1+4+ans['oentries']]
     if ordt2 > 0 and data[ordt2:ordt2+4] == b'ORDT':
diff --git a/src/calibre/ebooks/mobi/writer2/indexer.py b/src/calibre/ebooks/mobi/writer2/indexer.py
index cf847bdcb8..3c8eca2f29 100644
--- a/src/calibre/ebooks/mobi/writer2/indexer.py
+++ b/src/calibre/ebooks/mobi/writer2/indexer.py
@@ -221,7 +221,7 @@ class SecondaryIndexEntry(IndexEntry):
         tag = self.INDEX_MAP[index]
 
         # The values for this index entry
-        # I dont know what the 5 means, it is not the number of entries
+        # I don't know what the 5 means, it is not the number of entries
         self.secondary = [5 if tag == min(
             itervalues(self.INDEX_MAP)) else 0, 0, tag]
 
diff --git a/src/calibre/ebooks/mobi/writer2/main.py b/src/calibre/ebooks/mobi/writer2/main.py
index 022008ed0e..9c8e9ea6d9 100644
--- a/src/calibre/ebooks/mobi/writer2/main.py
+++ b/src/calibre/ebooks/mobi/writer2/main.py
@@ -20,7 +20,7 @@ from calibre.ebooks.mobi.writer2.serializer import Serializer
 from calibre.utils.filenames import ascii_filename
 from polyglot.builtins import iteritems
 
-# Disabled as I dont care about uncrossable breaks
+# Disabled as I don't care about uncrossable breaks
 WRITE_UNCROSSABLE_BREAKS = False
 NULL_INDEX = 0xffffffff
 
diff --git a/src/calibre/ebooks/mobi/writer2/resources.py b/src/calibre/ebooks/mobi/writer2/resources.py
index 5641bc2881..afe5befe69 100644
--- a/src/calibre/ebooks/mobi/writer2/resources.py
+++ b/src/calibre/ebooks/mobi/writer2/resources.py
@@ -25,7 +25,7 @@ def process_jpegs_for_amazon(data: bytes) -> bytes:
     img = Image.open(BytesIO(data))
     if img.format == 'JPEG':
         # Amazon's MOBI renderer can't render JPEG images without JFIF metadata
-        # and images with EXIF data dont get displayed on the cover screen
+        # and images with EXIF data don't get displayed on the cover screen
         changed = not img.info
         has_exif = False
         if hasattr(img, 'getexif'):
diff --git a/src/calibre/ebooks/mobi/writer2/serializer.py b/src/calibre/ebooks/mobi/writer2/serializer.py
index 3025f0f127..7d48491592 100644
--- a/src/calibre/ebooks/mobi/writer2/serializer.py
+++ b/src/calibre/ebooks/mobi/writer2/serializer.py
@@ -240,7 +240,7 @@ class Serializer:
                 if tocref.klass == 'periodical':
                     # This is a section node.
                     # For periodical tocs, the section urls are like r'feed_\d+/index.html'
-                    # We dont want to point to the start of the first article
+                    # We don't want to point to the start of the first article
                     # so we change the href.
                     itemhref = re.sub(r'article_\d+/', '', itemhref)
                 self.href_offsets[itemhref].append(buf.tell())
diff --git a/src/calibre/ebooks/mobi/writer8/index.py b/src/calibre/ebooks/mobi/writer8/index.py
index b09e3f91ad..692b00bbdd 100644
--- a/src/calibre/ebooks/mobi/writer8/index.py
+++ b/src/calibre/ebooks/mobi/writer8/index.py
@@ -246,7 +246,7 @@ class SkelIndex(Index):
     def __init__(self, skel_table):
         self.entries = [
                 (s.name, {
-                    # Dont ask me why these entries have to be repeated twice
+                    # Don't ask me why these entries have to be repeated twice
                     'chunk_count':(s.chunk_count, s.chunk_count),
                     'geometry':(s.start_pos, s.length, s.start_pos, s.length),
                     }) for s in skel_table
@@ -387,7 +387,7 @@ if __name__ == '__main__':
 
     subprocess.check_call(['ebook-convert', src, '.epub', '--level1-toc', '//h:p', '--no-default-epub-cover', '--flow-size', '1000000'])
     subprocess.check_call(['ebook-convert', src, '.azw3', '--level1-toc', '//h:p', '--no-inline-toc', '--extract-to=x'])
-    subprocess.call(['kindlegen', 'index.epub'])  # kindlegen exit code is not 0 as we dont have a cover
+    subprocess.call(['kindlegen', 'index.epub'])  # kindlegen exit code is not 0 as we don't have a cover
     subprocess.check_call(['calibre-debug', 'index.mobi'])
 
     from calibre.gui2.tweak_book.diff.main import main
diff --git a/src/calibre/ebooks/oeb/polish/container.py b/src/calibre/ebooks/oeb/polish/container.py
index 30a81d8b30..bef57a278d 100644
--- a/src/calibre/ebooks/oeb/polish/container.py
+++ b/src/calibre/ebooks/oeb/polish/container.py
@@ -500,7 +500,7 @@ class Container(ContainerBase):  # {{{
         # spec requires all text including filenames to be in NFC form.
         # The proper fix is to implement a VFS that maps between
         # canonical names and their file system representation, however,
-        # I dont have the time for that now. Note that the container
+        # I don't have the time for that now. Note that the container
         # ensures that all text files are normalized to NFC when
         # decoding them anyway, so there should be no mismatch between
         # names in the text and NFC canonical file names.
@@ -1481,7 +1481,7 @@ def opf_to_azw3(opf, outpath, container):
 
         def _parse_css(self, data):
             # The default CSS parser used by oeb.base inserts the h namespace
-            # and resolves all @import rules. We dont want that.
+            # and resolves all @import rules. We don't want that.
             return container.parse_css(data)
 
     def specialize(oeb):
diff --git a/src/calibre/ebooks/oeb/polish/embed.py b/src/calibre/ebooks/oeb/polish/embed.py
index 3572a7b190..3385b9ed2e 100644
--- a/src/calibre/ebooks/oeb/polish/embed.py
+++ b/src/calibre/ebooks/oeb/polish/embed.py
@@ -131,8 +131,8 @@ def filter_by_weight(fonts, val):
 
 def find_matching_font(fonts, weight='normal', style='normal', stretch='normal'):
     # See https://www.w3.org/TR/css-fonts-3/#font-style-matching
-    # We dont implement the unicode character range testing
-    # We also dont implement bolder, lighter
+    # We don't implement the unicode character range testing
+    # We also don't implement bolder, lighter
     for f, q in ((filter_by_stretch, stretch), (filter_by_style, style), (filter_by_weight, weight)):
         fonts = f(fonts, q)
         if len(fonts) == 1:
diff --git a/src/calibre/ebooks/oeb/polish/pretty.py b/src/calibre/ebooks/oeb/polish/pretty.py
index 6ec3de12ee..f49cddb316 100644
--- a/src/calibre/ebooks/oeb/polish/pretty.py
+++ b/src/calibre/ebooks/oeb/polish/pretty.py
@@ -81,7 +81,7 @@ def pretty_opf(root):
         try:
             children = sorted(manifest, key=manifest_key)
         except AttributeError:
-            continue  # There are comments so dont sort since that would mess up the comments
+            continue  # There are comments so don't sort since that would mess up the comments
         for x in reversed(children):
             manifest.insert(0, x)
 
diff --git a/src/calibre/ebooks/oeb/polish/tests/kepubify.py b/src/calibre/ebooks/oeb/polish/tests/kepubify.py
index e3c0bd1b1e..bca3e32d78 100644
--- a/src/calibre/ebooks/oeb/polish/tests/kepubify.py
+++ b/src/calibre/ebooks/oeb/polish/tests/kepubify.py
@@ -101,7 +101,7 @@ div#book-inner {{ margin-top: 0; margin-bottom: 0; }}</style><script type="text/
             # encoding quirks
             '<p>A\xa0nbsp;&nbsp;':
             '<p><span class="koboSpan" id="kobo.1.1">A&#160;nbsp;&#160;</span></p>',
-            '<div><script>1 < 2 & 3</script>':  # escaping with cdata note that kepubify doesnt do this
+            '<div><script>1 < 2 & 3</script>':  # escaping with cdata note that kepubify doesn't do this
             '<div><script><![CDATA[1 < 2 & 3]]></script></div>',
 
             # CSS filtering
diff --git a/src/calibre/ebooks/oeb/polish/utils.py b/src/calibre/ebooks/oeb/polish/utils.py
index 6cccf11d53..cc06d6bcf9 100644
--- a/src/calibre/ebooks/oeb/polish/utils.py
+++ b/src/calibre/ebooks/oeb/polish/utils.py
@@ -232,7 +232,7 @@ def parse_css(data, fname='<string>', is_declaration=False, decode=None, log_lev
     if css_preprocessor is not None:
         data = css_preprocessor(data)
     parser = CSSParser(loglevel=log_level,
-                        # We dont care about @import rules
+                        # We don't care about @import rules
                         fetcher=lambda x: (None, None), log=_css_logger)
     if is_declaration:
         data = parser.parseStyle(data, validate=False)
diff --git a/src/calibre/ebooks/oeb/transforms/cover.py b/src/calibre/ebooks/oeb/transforms/cover.py
index 278a715ed6..39194b7e0b 100644
--- a/src/calibre/ebooks/oeb/transforms/cover.py
+++ b/src/calibre/ebooks/oeb/transforms/cover.py
@@ -84,7 +84,7 @@ class CoverManager:
 
     def default_cover(self):
         '''
-        Create a generic cover for books that dont have a cover
+        Create a generic cover for books that don't have a cover
         '''
         if self.no_default_cover:
             return None
diff --git a/src/calibre/ebooks/oeb/transforms/embed_fonts.py b/src/calibre/ebooks/oeb/transforms/embed_fonts.py
index ffb33a7171..09ca8ea4fe 100644
--- a/src/calibre/ebooks/oeb/transforms/embed_fonts.py
+++ b/src/calibre/ebooks/oeb/transforms/embed_fonts.py
@@ -141,7 +141,7 @@ class EmbedFonts:
                 for sel in rule.selectorList:
                     sel = sel.selectorText
                     if sel and sel.startswith('.'):
-                        # We dont care about pseudo-selectors as the worst that
+                        # We don't care about pseudo-selectors as the worst that
                         # can happen is some extra characters will remain in
                         # the font
                         sel = sel.partition(':')[0]
diff --git a/src/calibre/ebooks/oeb/transforms/metadata.py b/src/calibre/ebooks/oeb/transforms/metadata.py
index a48589e62f..6abe700d22 100644
--- a/src/calibre/ebooks/oeb/transforms/metadata.py
+++ b/src/calibre/ebooks/oeb/transforms/metadata.py
@@ -144,7 +144,7 @@ class MergeMetadata:
             self.oeb.guide.remove('cover')
             self.oeb.guide.remove('titlepage')
         elif self.oeb.plumber_output_format in {'mobi', 'azw3'} and old_cover is not None:
-            # The amazon formats dont support html cover pages, so remove them
+            # The amazon formats don't support html cover pages, so remove them
             # even if no cover was specified.
             self.oeb.guide.remove('titlepage')
         do_remove_old_cover = False
diff --git a/src/calibre/ebooks/oeb/transforms/subset.py b/src/calibre/ebooks/oeb/transforms/subset.py
index cd9f0ebbe0..fe3fa3a7bd 100644
--- a/src/calibre/ebooks/oeb/transforms/subset.py
+++ b/src/calibre/ebooks/oeb/transforms/subset.py
@@ -214,7 +214,7 @@ class SubsetFonts:
                 for sel in rule.selectorList:
                     sel = sel.selectorText
                     if sel and sel.startswith('.'):
-                        # We dont care about pseudo-selectors as the worst that
+                        # We don't care about pseudo-selectors as the worst that
                         # can happen is some extra characters will remain in
                         # the font
                         sel = sel.partition(':')[0]
diff --git a/src/calibre/ebooks/pdf/html_writer.py b/src/calibre/ebooks/pdf/html_writer.py
index ef4cba7de4..1f3cf1110e 100644
--- a/src/calibre/ebooks/pdf/html_writer.py
+++ b/src/calibre/ebooks/pdf/html_writer.py
@@ -836,7 +836,7 @@ def fonts_are_identical(fonts):
 
 def merge_font_files(fonts, log):
     # As of Qt 5.15.1 Chromium has switched to harfbuzz and dropped sfntly. It
-    # now produces font descriptors whose W arrays dont match the glyph width
+    # now produces font descriptors whose W arrays don't match the glyph width
     # information from the hhea table, in contravention of the PDF spec. So
     # we can no longer merge font descriptors, all we can do is merge the
     # actual sfnt data streams into a single stream and subset it to contain
@@ -1013,7 +1013,7 @@ def add_header_footer(manager, opts, pdf_doc, container, page_number_display_map
         toplevel_toc_map = stack_to_map(create_toc_stack(tc()))
         toplevel_pagenum_map, toplevel_pages_map = page_counts_map(tc())
 
-    dpi = 96  # dont know how to query Qt for this, seems to be the same on all platforms
+    dpi = 96  # don't know how to query Qt for this, seems to be the same on all platforms
     def pt_to_px(pt): return int(pt * dpi / 72)
 
     def create_container(page_num, margins):
diff --git a/src/calibre/ebooks/pdf/reflow.py b/src/calibre/ebooks/pdf/reflow.py
index 34b44afa25..96d267080d 100644
--- a/src/calibre/ebooks/pdf/reflow.py
+++ b/src/calibre/ebooks/pdf/reflow.py
@@ -732,21 +732,21 @@ class Region:
 class Page:
 
     def __init__(self, page, font_map, opts, log, idc):
-        def text_cmp(frst, secnd):
+        def text_cmp(first, second):
             # Compare 2 text objects.
             # Order by line (top/bottom) then left
-            if (frst.top <= secnd.top and frst.bottom >= secnd.bottom-BOTTOM_FACTOR) \
-              or (secnd.top <= frst.top and secnd.bottom >= frst.bottom-BOTTOM_FACTOR):
+            if (first.top <= second.top and first.bottom >= second.bottom-BOTTOM_FACTOR) \
+              or (second.top <= first.top and second.bottom >= first.bottom-BOTTOM_FACTOR):
                 # Overlap = same line
-                if frst.left < secnd.left:
+                if first.left < second.left:
                     return -1
-                elif frst.left == secnd.left:
+                elif first.left == second.left:
                     return 0
                 return 1
             # Different line so sort into line number
-            if frst.bottom < secnd.bottom:
+            if first.bottom < second.bottom:
                 return -1
-            elif frst.bottom == secnd.bottom:
+            elif first.bottom == second.bottom:
                 return 0
             return 1
 
diff --git a/src/calibre/ebooks/rtf2xml/list_numbers.py b/src/calibre/ebooks/rtf2xml/list_numbers.py
index 736e0155b8..0951868cfc 100644
--- a/src/calibre/ebooks/rtf2xml/list_numbers.py
+++ b/src/calibre/ebooks/rtf2xml/list_numbers.py
@@ -121,7 +121,7 @@ class ListNumbers:
             return 'ordered'
         # sys.stderr.write('module is list_numbers\n')
         # sys.stderr.write('method is __determine type\n')
-        # sys.stderr.write('Couldn\'t get type of list\n')
+        # sys.stderr.write("Couldn't get type of list\n")
         # must be some type of ordered list -- just a guess!
         return 'unordered'
 
diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index e0aa43c22b..f18e1a38d4 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -1628,7 +1628,7 @@ def ensure_app(headless=True):
             # unhandled python exception in a slot or virtual method. Since ensure_app()
             # is used in worker processes for background work like rendering html
             # or running a headless browser, we circumvent this as I really
-            # dont feel like going through all the code and making sure no
+            # don't feel like going through all the code and making sure no
             # unhandled exceptions ever occur. All the actual GUI apps already
             # override sys.excepthook with a proper error handler.
             sys.excepthook = simple_excepthook
@@ -1776,7 +1776,7 @@ def raise_and_focus(self: QWidget) -> None:
 
 def raise_without_focus(self: QWidget) -> None:
     if QApplication.instance().platformName() == 'wayland':
-        # On fucking Wayland, we cant raise a dialog without also giving it
+        # On fucking Wayland, we can't raise a dialog without also giving it
         # keyboard focus. What a joke.
         self.raise_and_focus()
     else:
diff --git a/src/calibre/gui2/actions/__init__.py b/src/calibre/gui2/actions/__init__.py
index 6783235402..041d0ce011 100644
--- a/src/calibre/gui2/actions/__init__.py
+++ b/src/calibre/gui2/actions/__init__.py
@@ -269,7 +269,7 @@ class InterfaceAction(QObject):
                 else:
                     self.shortcut_action_for_context_menu = shortcut_action
                     if ismacos:
-                        # In Qt 5 keyboard shortcuts dont work unless the
+                        # In Qt 5 keyboard shortcuts don't work unless the
                         # action is explicitly added to the main window
                         self.gui.addAction(shortcut_action)
 
@@ -338,7 +338,7 @@ class InterfaceAction(QObject):
                 shortcut_name, default_keys=keys,
                 action=ac, description=description, group=self.action_spec[0],
                 persist_shortcut=persist_shortcut)
-            # In Qt 5 keyboard shortcuts dont work unless the
+            # In Qt 5 keyboard shortcuts don't work unless the
             # action is explicitly added to the main window and on OSX and
             # Unity since the menu might be exported, the shortcuts won't work
             self.gui.addAction(ac)
diff --git a/src/calibre/gui2/auto_add.py b/src/calibre/gui2/auto_add.py
index d1cae5e22c..5bf5b7b8af 100644
--- a/src/calibre/gui2/auto_add.py
+++ b/src/calibre/gui2/auto_add.py
@@ -288,10 +288,10 @@ class AutoAdder(QObject):
 
         if duplicates:
             paths, formats, metadata = [], [], []
-            for p, f, mis in duplicates:
+            for p, f, mi in duplicates:
                 paths.extend(p)
                 formats.extend(f)
-                metadata.extend(mis)
+                metadata.extend(mi)
             dups = [(mic, mic.cover, [p]) for mic, p in zip(metadata, paths)]
             d = DuplicatesQuestion(m.db, dups, parent=gui)
             dups = tuple(d.duplicates)
diff --git a/src/calibre/gui2/central.py b/src/calibre/gui2/central.py
index 54817cb14a..4af23199cf 100644
--- a/src/calibre/gui2/central.py
+++ b/src/calibre/gui2/central.py
@@ -485,7 +485,7 @@ class CentralContainer(QWidget):
 
     def read_settings(self):
         before = self.serialized_settings()
-        # sadly self.size() doesnt always return sensible values so look at
+        # sadly self.size() doesn't always return sensible values so look at
         # the size of the main window which works perfectly for width, not so
         # perfectly for height
         sz = self.size()
diff --git a/src/calibre/gui2/covers.py b/src/calibre/gui2/covers.py
index 6b601638a7..aef7235890 100644
--- a/src/calibre/gui2/covers.py
+++ b/src/calibre/gui2/covers.py
@@ -520,7 +520,7 @@ class CoverSettingsWidget(QWidget):
 
     def restore_defaults(self):
         defaults = self.original_prefs.defaults.copy()
-        # Dont delete custom color themes when restoring defaults
+        # Don't delete custom color themes when restoring defaults
         defaults['color_themes'] = self.custom_colors
         self.apply_prefs(defaults)
         self.update_preview()
diff --git a/src/calibre/gui2/dialogs/edit_category_notes.py b/src/calibre/gui2/dialogs/edit_category_notes.py
index 697d2b62f1..ae6948d05a 100644
--- a/src/calibre/gui2/dialogs/edit_category_notes.py
+++ b/src/calibre/gui2/dialogs/edit_category_notes.py
@@ -287,7 +287,7 @@ class NoteEditorWidget(EditorWidget):
 
     def do_insert_image(self):
         # See https://bugreports.qt.io/browse/QTBUG-118537
-        # for why we cant have a nice margin for floating images
+        # for why we can't have a nice margin for floating images
         d = AskImage(self.images, self.db)
         if d.exec() == QDialog.DialogCode.Accepted and d.current_digest:
             ir = self.images[d.current_digest]
diff --git a/src/calibre/gui2/email.py b/src/calibre/gui2/email.py
index 30f6650552..cf6005769c 100644
--- a/src/calibre/gui2/email.py
+++ b/src/calibre/gui2/email.py
@@ -153,21 +153,21 @@ def send_mails(jobnames, callback, attachments, to_s, subjects,
             attachments, to_s, subjects, texts, attachment_names):
         description = _('Email %(name)s to %(to)s') % dict(name=name, to=to)
         if isinstance(to, str) and (is_for_kindle(to) or '@pbsync.com' in to):
-            # The PocketBook service is a total joke. It cant handle
+            # The PocketBook service is a total joke. It can't handle
             # non-ascii, filenames that are long enough to be split up, commas, and
             # the good lord alone knows what else. So use a random filename
             # containing only 22 English letters and numbers
             #
             # And since this email is only going to be processed by automated
             # services, make the subject+text random too as at least the amazon
-            # service cant handle non-ascii text. I dont know what baboons
+            # service can't handle non-ascii text. I don't know what baboons
             # these companies employ to write their code. It's the height of
             # irony that they are called "tech" companies.
             # https://bugs.launchpad.net/calibre/+bug/1989282
             from calibre.utils.short_uuid import uuid4
             if not is_for_kindle(to):
                 # Amazon nowadays reads metadata from attachment filename instead of
-                # file internal metadata so dont nuke the filename.
+                # file internal metadata so don't nuke the filename.
                 # https://www.mobileread.com/forums/showthread.php?t=349290
                 aname = f'{uuid4()}.' + aname.rpartition('.')[-1]
             subject = uuid4()
diff --git a/src/calibre/gui2/fts/dialog.py b/src/calibre/gui2/fts/dialog.py
index 357a04c855..18905ba0c1 100644
--- a/src/calibre/gui2/fts/dialog.py
+++ b/src/calibre/gui2/fts/dialog.py
@@ -36,7 +36,7 @@ class FTSDialog(Dialog):
         l = QVBoxLayout(self)
         self.fat_warning = fw = QLabel(
             f'<span style="color:red; font-weight: bold">{_("WARNING")}:</span> ' +
-            _('The calibre library is on a FAT drive, indexing more than a few hundred books wont work.') +
+            _("The calibre library is on a FAT drive, indexing more than a few hundred books won't work.") +
             f' <a href="xxx" style="text-decoration: none">{_("Learn more")}</a>')
         # fw.setVisible(False)
         fw.linkActivated.connect(self.show_fat_details)
diff --git a/src/calibre/gui2/init.py b/src/calibre/gui2/init.py
index 9a44c2f7ff..be7d856b76 100644
--- a/src/calibre/gui2/init.py
+++ b/src/calibre/gui2/init.py
@@ -359,7 +359,7 @@ class VLTabs(QTabBar):  # {{{
     def lock_tab(self):
         gprefs['vl_tabs_closable'] = False
         self.setTabsClosable(False)
-        # Workaround for Qt bug where it doesnt recalculate the tab size after locking
+        # Workaround for Qt bug where it doesn't recalculate the tab size after locking
         for idx in range(self.count()):
             self.setTabButton(idx, QTabBar.ButtonPosition.RightSide, None)
             self.setTabButton(idx, QTabBar.ButtonPosition.LeftSide, None)
@@ -392,7 +392,7 @@ class VLTabs(QTabBar):  # {{{
 
     def tab_close(self, index):
         vl = str(self.tabData(index) or '')
-        if vl:  # Dont allow closing the All Books tab
+        if vl:  # Don't allow closing the All Books tab
             self.current_db.new_api.set_pref('virt_libs_hidden', list(
                 self.current_db.new_api.pref('virt_libs_hidden', ())) + [vl])
             self.removeTab(index)
diff --git a/src/calibre/gui2/library/alternate_views.py b/src/calibre/gui2/library/alternate_views.py
index 2e3df1df72..24069c7e92 100644
--- a/src/calibre/gui2/library/alternate_views.py
+++ b/src/calibre/gui2/library/alternate_views.py
@@ -646,7 +646,7 @@ class CoverDelegate(QStyledItemDelegate):
                 if self.title_height != 0:
                     self.paint_title(painter, trect, db, book_id)
             if self.emblem_size > 0:
-                # We dont draw embossed emblems as the ondevice/marked emblems are drawn in the gutter
+                # We don't draw embossed emblems as the ondevice/marked emblems are drawn in the gutter
                 return
             if marked:
                 try:
@@ -1163,7 +1163,7 @@ class GridView(QListView):
             self.thumbnail_cache.set_database(newdb)
             try:
                 # Use a timeout so that if, for some reason, the render thread
-                # gets stuck, we dont deadlock, future covers won't get
+                # gets stuck, we don't deadlock, future covers won't get
                 # rendered, but this is better than a deadlock
                 join_with_timeout(self.delegate.render_queue)
             except RuntimeError:
diff --git a/src/calibre/gui2/library/models.py b/src/calibre/gui2/library/models.py
index ed80eaf09a..d89eeac5f1 100644
--- a/src/calibre/gui2/library/models.py
+++ b/src/calibre/gui2/library/models.py
@@ -243,7 +243,7 @@ class BooksModel(QAbstractTableModel):  # {{{
         self.bool_yes_icon = QIcon.ic('ok.png').pixmap(icon_height)
         self.bool_no_icon = QIcon.ic('list_remove.png').pixmap(icon_height)
         self.bool_blank_icon = QIcon.ic('blank.png').pixmap(icon_height)
-        # Qt auto-scales marked icon correctly, so we dont need to do it (and
+        # Qt auto-scales marked icon correctly, so we don't need to do it (and
         # remember that the cover grid view needs a larger version of the icon,
         # anyway)
         self.marked_icon = QIcon.ic('marked.png')
diff --git a/src/calibre/gui2/library/views.py b/src/calibre/gui2/library/views.py
index 8d2a745b79..9117ee2319 100644
--- a/src/calibre/gui2/library/views.py
+++ b/src/calibre/gui2/library/views.py
@@ -164,7 +164,7 @@ class PreserveViewState:  # {{{
     '''
     Save the set of selected books at enter time. If at exit time there are no
     selected books, restore the previous selection, the previous current index
-    and dont affect the scroll position.
+    and don't affect the scroll position.
     '''
 
     def __init__(self, view, preserve_hpos=True, preserve_vpos=True, require_selected_ids=True):
diff --git a/src/calibre/gui2/markdown_syntax_highlighter.py b/src/calibre/gui2/markdown_syntax_highlighter.py
index f26c0f23aa..353a36eb1d 100644
--- a/src/calibre/gui2/markdown_syntax_highlighter.py
+++ b/src/calibre/gui2/markdown_syntax_highlighter.py
@@ -268,7 +268,7 @@ class MarkdownHighlighter(QSyntaxHighlighter):
             elif emphasis:
                 self.setFormat(self.offset+offset+ match.start(), match.end() - match.start(), self.MARKDOWN_KWS_FORMAT['Italic'])
 
-        def recusive(match, extra_offset, bold, emphasis):
+        def recursive(match, extra_offset, bold, emphasis):
             apply(match, bold, emphasis)
             if bold and emphasis:
                 return  # max deep => return, do not process extra Bold/Italic
@@ -278,17 +278,17 @@ class MarkdownHighlighter(QSyntaxHighlighter):
             self._highlightBoldEmphasis(sub_txt, cursor, bf, sub_offset, bold, emphasis)
 
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['Italic'],text):
-            recusive(mo, 1, bold, True)
+            recursive(mo, 1, bold, True)
             found = True
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['uItalic'],text):
-            recusive(mo, 1, bold, True)
+            recursive(mo, 1, bold, True)
             found = True
 
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['Bold'],text):
-            recusive(mo, 2, True, emphasis)
+            recursive(mo, 2, True, emphasis)
             found = True
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['uBold'],text):
-            recusive(mo, 2, True, emphasis)
+            recursive(mo, 2, True, emphasis)
             found = True
 
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['BoldItalic'],text):
diff --git a/src/calibre/gui2/notify.py b/src/calibre/gui2/notify.py
index 3cc81213ef..b419b38eb1 100644
--- a/src/calibre/gui2/notify.py
+++ b/src/calibre/gui2/notify.py
@@ -253,7 +253,7 @@ def get_notifier(systray=None):
             if not ans.ok:
                 ans = DummyNotifier()
         else:
-            # We dont use Qt's systray based notifier as it uses Growl and is
+            # We don't use Qt's systray based notifier as it uses Growl and is
             # broken with different versions of Growl
             ans = DummyNotifier()
     elif iswindows:
diff --git a/src/calibre/gui2/pictureflow/pictureflow.cpp b/src/calibre/gui2/pictureflow/pictureflow.cpp
index 912b1a9ea4..9b0e094ee4 100644
--- a/src/calibre/gui2/pictureflow/pictureflow.cpp
+++ b/src/calibre/gui2/pictureflow/pictureflow.cpp
@@ -965,7 +965,7 @@ QRect PictureFlowPrivate::renderSlide(const SlideInfo &slide, int alpha, int col
     if(column < 0)
       continue;
     if (preserveAspectRatio && !slide_moving_to_center) {
-        // We dont want a black border at the edge of narrow images when the images are in the left or right stacks
+        // We don't want a black border at the edge of narrow images when the images are in the left or right stacks
         if (slide.slideIndex < centerIndex) {
             column = qMin(column + img_offset, sw - 1);
         } else if (slide.slideIndex == centerIndex) {
diff --git a/src/calibre/gui2/progress_indicator/CalibreStyle.cpp b/src/calibre/gui2/progress_indicator/CalibreStyle.cpp
index b9512831bf..14abe528e9 100644
--- a/src/calibre/gui2/progress_indicator/CalibreStyle.cpp
+++ b/src/calibre/gui2/progress_indicator/CalibreStyle.cpp
@@ -290,7 +290,7 @@ void CalibreStyle::drawPrimitive(PrimitiveElement element, const QStyleOption *
     const QStyleOptionViewItem *vopt = NULL;
     switch (element) {
         case PE_FrameTabBarBase: // {{{
-            // dont draw line below tabs in dark mode as it looks bad
+            // don't draw line below tabs in dark mode as it looks bad
             if (const QStyleOptionTabBarBase *tbb = qstyleoption_cast<const QStyleOptionTabBarBase *>(option)) {
                 if (tbb->shape == QTabBar::RoundedNorth) {
                     QColor bg = option->palette.color(QPalette::Window);
diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index 4197098986..59c688a401 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -80,7 +80,7 @@ def beautify_text(raw, syntax):
         log.setLevel(logging.WARN)
         log.raiseExceptions = False
         parser = CSSParser(loglevel=logging.WARNING,
-                           # We dont care about @import rules
+                           # We don't care about @import rules
                            fetcher=lambda x: (None, None), log=_css_logger)
         data = parser.parseString(raw, href='<string>', validate=False)
         return serialize(data, 'text/css').decode('utf-8')
diff --git a/src/calibre/gui2/tweak_book/editor/snippets.py b/src/calibre/gui2/tweak_book/editor/snippets.py
index 6ef59672ea..0c60275134 100644
--- a/src/calibre/gui2/tweak_book/editor/snippets.py
+++ b/src/calibre/gui2/tweak_book/editor/snippets.py
@@ -46,7 +46,7 @@ from polyglot.builtins import codepoint_to_chr, iteritems, itervalues
 
 
 def string_length(x):
-    return strlen(str(x))  # Needed on narrow python builds, as subclasses of unicode dont work
+    return strlen(str(x))  # Needed on narrow python builds, as subclasses of unicode don't work
 
 
 KEY = Qt.Key.Key_J
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
index 3cc1605e80..2b0de9a9e8 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
@@ -25,7 +25,7 @@ JS_IDENT = JS_IDENT_START + '(?:' + JS_IDENT_PART + ')*'
 class JavascriptLexer(RegexLexer):
     '''
     For JavaScript source code. This is based on the pygments JS highlighter,
-    bu that does not handle multi-line comments in streaming mode, so we had to
+    but that does not handle multi-line comments in streaming mode, so we had to
     modify it.
     '''
 
diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index 1326dba6eb..e74035293c 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -877,7 +877,7 @@ class TextEdit(PlainTextEdit):
         c = self.textCursor()
         left = min(c.anchor(), c.position())
         right = max(c.anchor(), c.position())
-        # For speed we use QPlainTextEdit's toPlainText as we dont care about
+        # For speed we use QPlainTextEdit's toPlainText as we don't care about
         # spaces in this context
         raw = str(QPlainTextEdit.toPlainText(self))
         # Make sure the left edge is not within a <>
diff --git a/src/calibre/gui2/tweak_book/search.py b/src/calibre/gui2/tweak_book/search.py
index 9503e91e60..7457e96428 100644
--- a/src/calibre/gui2/tweak_book/search.py
+++ b/src/calibre/gui2/tweak_book/search.py
@@ -1346,7 +1346,7 @@ def get_search_function(state):
     ans = state['replace']
     is_regex = state['mode'] not in ('normal', 'fuzzy')
     if not is_regex:
-        # We dont want backslash escape sequences interpreted in normal mode
+        # We don't want backslash escape sequences interpreted in normal mode
         return lambda m: ans
     if state['mode'] == 'function':
         try:
diff --git a/src/calibre/gui2/wizard/__init__.py b/src/calibre/gui2/wizard/__init__.py
index 960f2a048c..bbdb90c7fb 100644
--- a/src/calibre/gui2/wizard/__init__.py
+++ b/src/calibre/gui2/wizard/__init__.py
@@ -862,7 +862,7 @@ class LibraryPage(QWizardPage, LibraryUI):
                 os.rmdir(dln)
         except Exception:
             pass
-        # dont leave behind any empty dirs
+        # don't leave behind any empty dirs
         for x in self.made_dirs:
             with suppress(OSError):
                 os.rmdir(x)
diff --git a/src/calibre/library/catalogs/epub_mobi_builder.py b/src/calibre/library/catalogs/epub_mobi_builder.py
index f72f716d02..124660e9be 100644
--- a/src/calibre/library/catalogs/epub_mobi_builder.py
+++ b/src/calibre/library/catalogs/epub_mobi_builder.py
@@ -3888,7 +3888,7 @@ class CatalogBuilder:
             if zf is not None:
                 # Ensure that the read succeeded
                 # If we failed to open the zip file for reading,
-                # we dont know if it contained the thumb or not
+                # we don't know if it contained the thumb or not
                 zf = _open_archive('a')
                 if zf is not None:
                     with zf:
diff --git a/src/calibre/srv/auth.py b/src/calibre/srv/auth.py
index 86d3cc4883..a5b5a0cf46 100644
--- a/src/calibre/srv/auth.py
+++ b/src/calibre/srv/auth.py
@@ -200,7 +200,7 @@ class DigestAuth:  # {{{
 
     def validate_request(self, pw, data, log=None):
         # We should also be checking for replay attacks by using nonce_count,
-        # however, various HTTP clients, most prominently Firefox dont
+        # however, various HTTP clients, most prominently Firefox don't
         # implement nonce-counts correctly, so we cannot do the check.
         # https://bugzil.la/114451
         path = parse_uri(self.uri.encode('utf-8'))[1]
diff --git a/src/calibre/srv/content.py b/src/calibre/srv/content.py
index 44733abc30..a7e4e89902 100644
--- a/src/calibre/srv/content.py
+++ b/src/calibre/srv/content.py
@@ -541,7 +541,7 @@ def get_data_file(ctx, rd, book_id, relpath, library_id):
 
 
 def strerr(e: Exception):
-    # Dont leak the filepath in the error response
+    # Don't leak the filepath in the error response
     if isinstance(e, OSError):
         return e.strerror or str(e)
     return str(e)
diff --git a/src/calibre/srv/http_request.py b/src/calibre/srv/http_request.py
index 384a0613f1..ba5d3b33cf 100644
--- a/src/calibre/srv/http_request.py
+++ b/src/calibre/srv/http_request.py
@@ -83,7 +83,7 @@ def parse_uri(uri, parse_query=True, unquote_func=unquote):
         try:
             query = MultiDict.create_from_query_string(qs)
         except Exception:
-            raise HTTPSimpleResponse(http_client.BAD_REQUEST, 'Unparseable query string')
+            raise HTTPSimpleResponse(http_client.BAD_REQUEST, 'Unparsable query string')
     else:
         query = None
 
diff --git a/src/calibre/srv/loop.py b/src/calibre/srv/loop.py
index 7e5960d4eb..8d4f4e677e 100644
--- a/src/calibre/srv/loop.py
+++ b/src/calibre/srv/loop.py
@@ -256,7 +256,7 @@ class Connection:  # {{{
 
     def recv(self, amt):
         # If there is data in the read buffer we have to return only that,
-        # since we dont know if the socket has signalled it is ready for
+        # since we don't know if the socket has signalled it is ready for
         # reading
         if self.read_buffer.has_data:
             return self.read_buffer.read(amt)
diff --git a/src/calibre/srv/metadata.py b/src/calibre/srv/metadata.py
index 35fdca42c0..6433f9fbe1 100644
--- a/src/calibre/srv/metadata.py
+++ b/src/calibre/srv/metadata.py
@@ -233,7 +233,7 @@ class GroupedSearchTerms:
     def __init__(self, src):
         self.keys = frozenset(src)
         self.hash = hash(self.keys)
-        # We dont need to store values since this is used as part of a key for
+        # We don't need to store values since this is used as part of a key for
         # a cache and if the values have changed the cache will be invalidated
         # for other reasons anyway (last_modified() will have changed on the
         # db)
diff --git a/src/calibre/srv/routes.py b/src/calibre/srv/routes.py
index 6cf85dbc13..3f3a6fad40 100644
--- a/src/calibre/srv/routes.py
+++ b/src/calibre/srv/routes.py
@@ -295,7 +295,7 @@ class Router:
                 if x:
                     k, v = x.partition('=')[::2]
                     if k:
-                        # Since we only set simple hex encoded cookies, we dont
+                        # Since we only set simple hex encoded cookies, we don't
                         # need more sophisticated value parsing
                         c[k] = v.strip('"')
 
diff --git a/src/calibre/utils/browser.py b/src/calibre/utils/browser.py
index d416ebbb29..a776eb62c9 100644
--- a/src/calibre/utils/browser.py
+++ b/src/calibre/utils/browser.py
@@ -31,7 +31,7 @@ class ModernHTTPSHandler(HTTPSHandler):
 
 class Browser(B):
     '''
-    A cloneable mechanize browser. Useful for multithreading. The idea is that
+    A clonable mechanize browser. Useful for multithreading. The idea is that
     each thread has a browser clone. Every clone uses the same thread safe
     cookie jar. All clones share the same browser configuration.
 
diff --git a/src/calibre/utils/copy_files.py b/src/calibre/utils/copy_files.py
index 94f96f36f0..f49a11e94a 100644
--- a/src/calibre/utils/copy_files.py
+++ b/src/calibre/utils/copy_files.py
@@ -153,7 +153,7 @@ class WindowsFileCopier:
                 except OSError as err:
                     # Ignore dir not empty errors. Should never happen but we
                     # ignore it as the UNIX semantics are to not delete folders
-                    # during __exit__ anyway and we dont want to leak the handle.
+                    # during __exit__ anyway and we don't want to leak the handle.
                     if err.winerror != winutil.ERROR_DIR_NOT_EMPTY:
                         raise
             h.close()
diff --git a/src/calibre/utils/filenames.py b/src/calibre/utils/filenames.py
index 9633a79550..5182f75ea6 100644
--- a/src/calibre/utils/filenames.py
+++ b/src/calibre/utils/filenames.py
@@ -222,7 +222,7 @@ def case_preserving_open_file(path, mode='wb', mkdir_mode=0o777):
         try:
             candidates = [c for c in os.listdir(cpath) if c.lower() == cl]
         except:
-            # Dont have permission to do the listdir, assume the case is
+            # Don't have permission to do the listdir, assume the case is
             # correct as we have no way to check it.
             pass
         else:
diff --git a/src/calibre/utils/fonts/scanner.py b/src/calibre/utils/fonts/scanner.py
index 7452c23bab..8ec3c1585d 100644
--- a/src/calibre/utils/fonts/scanner.py
+++ b/src/calibre/utils/fonts/scanner.py
@@ -315,8 +315,8 @@ class FontScanner(Thread):
         self.reload_cache()
 
         if isworker:
-            # Dont scan font files in worker processes, use whatever is
-            # cached. Font files typically dont change frequently enough to
+            # Don't scan font files in worker processes, use whatever is
+            # cached. Font files typically don't change frequently enough to
             # justify a rescan in a worker process.
             self.build_families()
             return
diff --git a/src/calibre/utils/formatter.py b/src/calibre/utils/formatter.py
index fc31f35fbe..6dfeb7819c 100644
--- a/src/calibre/utils/formatter.py
+++ b/src/calibre/utils/formatter.py
@@ -192,7 +192,7 @@ class SetGlobalsNode(Node):
 
 class StringCompareNode(Node):
     def __init__(self, line_number, operator, left, right):
-        Node.__init__(self, line_number, 'comparision: ' + operator)
+        Node.__init__(self, line_number, 'comparison: ' + operator)
         self.node_type = self.NODE_COMPARE_STRING
         self.operator = operator
         self.left = left
diff --git a/src/calibre/utils/icu.c b/src/calibre/utils/icu.c
index 58053bb520..5952187194 100644
--- a/src/calibre/utils/icu.c
+++ b/src/calibre/utils/icu.c
@@ -374,7 +374,7 @@ icu_Collator_contractions(icu_Collator *self, PyObject *args) {
             if (pbuf == NULL) { Py_DECREF(ans); ans = NULL; goto end; }
             PyTuple_SetItem(ans, i, pbuf);
         } else {
-            // Ranges dont make sense for contractions, ignore them
+            // Ranges don't make sense for contractions, ignore them
             PyTuple_SetItem(ans, i, Py_None); Py_INCREF(Py_None);
         }
     }
diff --git a/src/calibre/utils/inotify.py b/src/calibre/utils/inotify.py
index e3636cd4cf..7a48a38876 100644
--- a/src/calibre/utils/inotify.py
+++ b/src/calibre/utils/inotify.py
@@ -248,7 +248,7 @@ class INotifyTreeWatcher(INotify):
                     raise NoSuchDir(f'The dir {base} does not exist')
                 return
             if e.errno == errno.EACCES:
-                # We silently ignore entries for which we dont have permission,
+                # We silently ignore entries for which we don't have permission,
                 # unless they are the top level dir
                 if top_level:
                     raise NoSuchDir(f'You do not have permission to monitor {base}')
@@ -293,7 +293,7 @@ class INotifyTreeWatcher(INotify):
 
     def process_event(self, wd, mask, cookie, name):
         if wd == -1 and (mask & self.Q_OVERFLOW):
-            # We missed some INOTIFY events, so we dont
+            # We missed some INOTIFY events, so we don't
             # know the state of any tracked dirs.
             self.watch_tree()
             self.modified.add(None)
diff --git a/src/calibre/utils/iphlpapi.py b/src/calibre/utils/iphlpapi.py
index 0e17173c09..ffbc6f6452 100644
--- a/src/calibre/utils/iphlpapi.py
+++ b/src/calibre/utils/iphlpapi.py
@@ -202,7 +202,7 @@ class IP_ADAPTER_ADDRESSES(ctypes.Structure):
         ('Dhcpv6ClientDuid', ctypes.c_ubyte * MAX_DHCPV6_DUID_LENGTH),
         ('Dhcpv6ClientDuidLength', wintypes.ULONG),
         ('Dhcpv6Iaid', wintypes.ULONG),
-        # Vista SP1 and later, so we comment it out as we dont need it
+        # Vista SP1 and later, so we comment it out as we don't need it
         # ('FirstDnsSuffix', ctypes.POINTER(IP_ADAPTER_DNS_SUFFIX)),
     ]
 
diff --git a/src/calibre/utils/ipython.py b/src/calibre/utils/ipython.py
index 16f5396f32..3a7672f7cd 100644
--- a/src/calibre/utils/ipython.py
+++ b/src/calibre/utils/ipython.py
@@ -113,8 +113,8 @@ history_length(2000) #value of -1 means no limit
         if not os.path.exists(ipydir):
             os.makedirs(ipydir)
         conf = os.path.join(ipydir, 'pyreadline.txt')
-        hist = os.path.join(ipydir, 'history.txt')
-        config = config % hist
+        history = os.path.join(ipydir, 'history.txt')
+        config = config % history
         with open(conf, 'wb') as f:
             f.write(config.encode('utf-8'))
         pyreadline.rlmain.config_path = conf
diff --git a/src/calibre/utils/smtplib.py b/src/calibre/utils/smtplib.py
index 1964ab6a87..61be1e905d 100644
--- a/src/calibre/utils/smtplib.py
+++ b/src/calibre/utils/smtplib.py
@@ -743,7 +743,7 @@ class SMTP:
          >>> tolist=["one@one.org","two@two.org","three@three.org","four@four.org"]
          >>> msg = '''\\
          ... From: Me@my.org
-         ... Subject: testin'...
+         ... Subject: testing...
          ...
          ... This is a test '''
          >>> s.sendmail("me@my.org",tolist,msg)
diff --git a/src/calibre/utils/zipfile.py b/src/calibre/utils/zipfile.py
index 912e54eb9c..639d84ba28 100644
--- a/src/calibre/utils/zipfile.py
+++ b/src/calibre/utils/zipfile.py
@@ -293,7 +293,7 @@ def _EndRecData(fpin):
         endrec = list(struct.unpack(structEndArchive, recData))
         comment = data[start+sizeEndCentDir:]
         # check that comment length is correct
-        # Kovid: Added == 0 check as some zip files apparently dont set this
+        # Kovid: Added == 0 check as some zip files apparently don't set this
         if endrec[_ECD_COMMENT_SIZE] == 0 or endrec[_ECD_COMMENT_SIZE] == len(comment):
             # Append the archive comment and start offset
             endrec.append(comment)
diff --git a/src/pyj/book_list/search.pyj b/src/pyj/book_list/search.pyj
index 5491d9749d..d0f6270ac7 100644
--- a/src/pyj/book_list/search.pyj
+++ b/src/pyj/book_list/search.pyj
@@ -457,7 +457,7 @@ def create_search_panel(container):
     ))
 
     # Build search input
-    # We dont focus the search box because on mobile that will cause the
+    # We don't focus the search box because on mobile that will cause the
     # keyboard to popup and obscure the rest of the page
     search_container = component(container, 'search')
     search_button = create_button(_('Search'), icon='search', tooltip=_('Do the search'))
diff --git a/src/pyj/range_utils.pyj b/src/pyj/range_utils.pyj
index d677d3df99..e5acffa0ca 100644
--- a/src/pyj/range_utils.pyj
+++ b/src/pyj/range_utils.pyj
@@ -176,7 +176,7 @@ def create_wrapper_function(wrapper_elem, r, intersecting_wrappers, process_wrap
             end_node = current_wrapper
             end_offset = 1
         if current_range.collapsed:
-            # Dont wrap empty ranges. This is needed otherwise two adjacent
+            # Don't wrap empty ranges. This is needed otherwise two adjacent
             # selections of text will incorrectly be detected as overlapping.
             # For example: highlight abc then def in the word abcdef here the
             # second highlight's first range is the collapsed range at the end
diff --git a/src/pyj/read_book/cfi.pyj b/src/pyj/read_book/cfi.pyj
index 6cbdd254af..055c7e347f 100644
--- a/src/pyj/read_book/cfi.pyj
+++ b/src/pyj/read_book/cfi.pyj
@@ -105,7 +105,7 @@ def find_offset_for_point(x, y, node, cdoc):
                 return v'[child, offset_in_text_node(child, range_, x, y)]'
         child = child.nextSibling
 
-    # The point must be after the last bit of text/in the padding/border, we dont know
+    # The point must be after the last bit of text/in the padding/border, we don't know
     # how to get a good point in this case
     return None, None
 
@@ -304,7 +304,7 @@ def node_for_text_offset(nodes, offset, first_node):
                 return node, offset, True
             last_text_node = node
             offset -= l
-        # mathml nodes dont have dataset
+        # mathml nodes don't have dataset
         elif node.nodeType is Node.ELEMENT_NODE and node.dataset?.calibreRangeWrapper:
             qn, offset, ok = node_for_text_offset(unwrapped_nodes(node), offset)
             if ok:
diff --git a/src/pyj/read_book/iframe.pyj b/src/pyj/read_book/iframe.pyj
index 01ed1e776d..2e97e31a90 100644
--- a/src/pyj/read_book/iframe.pyj
+++ b/src/pyj/read_book/iframe.pyj
@@ -260,7 +260,7 @@ class IframeBoss:
             console.log(f'Unhandled error from external javascript, ignoring: {msg} {script_url} {line_number}')
             return
         is_internal_error = script_url in ('about:srcdoc', 'userscript:viewer.js')
-        if is_internal_error:  # dont report errors from scripts in the book itself
+        if is_internal_error:  # don't report errors from scripts in the book itself
             console.log(f'{script_url}: {error_object}')
             try:
                 fname = script_url.rpartition('/')[-1] or script_url
diff --git a/src/pyj/read_book/overlay.pyj b/src/pyj/read_book/overlay.pyj
index 096502ff9f..fb5bbd374a 100644
--- a/src/pyj/read_book/overlay.pyj
+++ b/src/pyj/read_book/overlay.pyj
@@ -64,7 +64,7 @@ class LoadingMessage:  # {{{
         safe_set_inner_html(container.firstChild.lastChild, self.msg)
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 # }}}
 
 class DeleteBook:  # {{{
@@ -116,7 +116,7 @@ class DeleteBook:  # {{{
         safe_set_inner_html(container.lastChild.lastChild, _('Deleting local book copy, please wait...'))
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def delete_book(self):
         if runtime.is_standalone_viewer:
@@ -165,7 +165,7 @@ class SyncBook:  # {{{
         ))
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def cancel(self):
         self.canceled = True
@@ -489,7 +489,7 @@ class SimpleOverlay:  # {{{
         self.title = title
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def show(self, container):
         simple_overlay_title(self.title, self.overlay, container)
@@ -524,7 +524,7 @@ class WordActionsOverlay:  # {{{
         self.overlay = overlay
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def show(self, container):
         simple_overlay_title(_('Lookup: {}').format(self.word), self.overlay, container)
@@ -538,7 +538,7 @@ class PrefsOverlay: # {{{
         self.changes_occurred = False
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def create_panel_impl(self, container):
         return create_prefs_panel(container, self.overlay.hide_current_panel, self.on_change)
@@ -592,7 +592,7 @@ class OpenBook: # {{{
                 ui_operations.quit()
 
     def on_container_click(self, evt):
-        pass  # Dont allow panel to be closed by a click
+        pass  # Don't allow panel to be closed by a click
 
     def show(self, container):
         simple_overlay_title(_('Open a book'), self.overlay, container, def ():
diff --git a/src/pyj/read_book/paged_mode.pyj b/src/pyj/read_book/paged_mode.pyj
index 0cf8f0de1b..a5802cac9b 100644
--- a/src/pyj/read_book/paged_mode.pyj
+++ b/src/pyj/read_book/paged_mode.pyj
@@ -80,7 +80,7 @@ is_full_screen_layout = False
 
 
 def get_number_of_cols(dont_return_integer):
-    # we dont store this because of the chrome resize bug where the document width
+    # we don't store this because of the chrome resize bug where the document width
     # sometimes changes a few milliseconds after layout in paged mode
     if is_full_screen_layout:
         return 1
@@ -446,7 +446,7 @@ def next_screen_location():
         current_pos = Math.ceil(current_scroll_offset())
         ans = limit if current_pos < limit else -1
         if cols_per_screen is 1 and ans is not -1 and ans - current_pos < col_size:
-            ans = -1  # cant scroll partial columns
+            ans = -1  # can't scroll partial columns
     return ans
 
 
@@ -769,7 +769,7 @@ def scroll_by_page(backward, by_screen, flip_if_rtl_page_progression):
         pos = previous_col_location() if backward else next_col_location()
         pages = 1
     if pos is -1:
-        # dont report human scroll since we dont know if a full page was
+        # don't report human scroll since we don't know if a full page was
         # scrolled or not
         next_spine_item(backward)
     else:
diff --git a/src/pyj/read_book/selection_bar.pyj b/src/pyj/read_book/selection_bar.pyj
index 2729a48fc7..0e82e41ab1 100644
--- a/src/pyj/read_book/selection_bar.pyj
+++ b/src/pyj/read_book/selection_bar.pyj
@@ -693,7 +693,7 @@ class SelectionBar:
         self.drag_scroll_timer = window.setTimeout(self.do_one_drag_scroll.bind(None, backwards, distance_from_boundary), interval)
         now = window.performance.now()
         if self.last_drag_scroll_at is None:
-            # dont jump a page immediately in paged mode
+            # don't jump a page immediately in paged mode
             if in_flow_mode:
                 self.send_drag_scroll_message(backwards, 'left' if self.dragging_handle is self.start_handle_id else 'right', True)
             self.last_drag_scroll_at = now
@@ -782,7 +782,7 @@ class SelectionBar:
         buffer = 2
         limits = {
             'top': buffer, 'bottom': container.offsetHeight - bar_height - buffer,
-            # - 10 ensures we dont cover scroll bar
+            # - 10 ensures we don't cover scroll bar
             'left': buffer, 'right': container.offsetWidth - bar_width - buffer - 10
         }
         start_handle, end_handle = self.start_handle, self.end_handle
diff --git a/src/pyj/read_book/ui.pyj b/src/pyj/read_book/ui.pyj
index 82f80b390c..1db4f1eddb 100644
--- a/src/pyj/read_book/ui.pyj
+++ b/src/pyj/read_book/ui.pyj
@@ -145,7 +145,7 @@ class ReadUI:
                 try:
                     result = JSON.parse(xhr.responseText)
                 except Exception:
-                    return self.show_error(_('Failed to parse profiles'), _('Unparseable data received for profiles'))
+                    return self.show_error(_('Failed to parse profiles'), _('Unparsable data received for profiles'))
                 proceed(result)
             ).send()
 
diff --git a/src/pyj/read_book/view.pyj b/src/pyj/read_book/view.pyj
index 950d1abc99..7d253b44ff 100644
--- a/src/pyj/read_book/view.pyj
+++ b/src/pyj/read_book/view.pyj
@@ -868,7 +868,7 @@ class View:
         self.content_popup_overlay.apply_color_scheme(ans.background, ans.foreground)
         self.book_scrollbar.apply_color_scheme(ans)
         # this is needed on iOS where the bottom margin has its own margin,
-        # so we dont want the body background color to bleed through
+        # so we don't want the body background color to bleed through
         iframe.parentNode.style.backgroundColor = ans.background
         iframe.parentNode.parentNode.style.backgroundColor = ans.background
         return ans
diff --git a/src/pyj/select.pyj b/src/pyj/select.pyj
index 7ed3d9275a..ef0aa7c8eb 100644
--- a/src/pyj/select.pyj
+++ b/src/pyj/select.pyj
@@ -134,7 +134,7 @@ def range_extents(q, in_flow_mode):
                         rect = boundary_node.getBoundingClientRect()
                         if not is_start:
                             ans.selected_prev = True
-                # we cant use getBoundingClientRect as the node might be split
+                # we can't use getBoundingClientRect as the node might be split
                 # among multiple columns
                 else if node.getClientRects:
                     rects = node.getClientRects()