diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index bb5c26a50c..c5ebae4bba 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -184,14 +184,14 @@ class Dehyphenator(object):
             wraptags = match.group('wraptags')
         except:
             wraptags = ''
-        hyphenated = str(firsthalf) + "-" + str(secondhalf)
-        dehyphenated = str(firsthalf) + str(secondhalf)
+        hyphenated = unicode(firsthalf) + "-" + unicode(secondhalf)
+        dehyphenated = unicode(firsthalf) + unicode(secondhalf)
         lookupword = self.removesuffixes.sub('', dehyphenated)
         if self.prefixes.match(firsthalf) is None:
            lookupword = self.removeprefix.sub('', lookupword)
         #print "lookup word is: "+str(lookupword)+", orig is: " + str(hyphenated)
         try:
-            searchresult = self.html.find(str.lower(lookupword))
+            searchresult = self.html.find(lookupword.lower())
         except:
             return hyphenated
         if self.format == 'html_cleanup':
diff --git a/src/calibre/ebooks/conversion/utils.py b/src/calibre/ebooks/conversion/utils.py
index 5f5c12a703..2faec27b68 100644
--- a/src/calibre/ebooks/conversion/utils.py
+++ b/src/calibre/ebooks/conversion/utils.py
@@ -22,18 +22,21 @@ class PreProcessor(object):
         title = match.group('title')
         if not title:
             self.html_preprocess_sections = self.html_preprocess_sections + 1
-            self.log("found " + str(self.html_preprocess_sections) + " chapters. - " + str(chap))
+            self.log("found " + unicode(self.html_preprocess_sections) +
+                    " chapters. - " + unicode(chap))
             return '<h2>'+chap+'</h2>\n'
         else:
             self.html_preprocess_sections = self.html_preprocess_sections + 1
-            self.log("found " + str(self.html_preprocess_sections) + " chapters & titles. - " + str(chap) + ", " + str(title))
+            self.log("found " + unicode(self.html_preprocess_sections) +
+                    " chapters & titles. - " + unicode(chap) + ", " + unicode(title))
             return '<h2>'+chap+'</h2>\n<h3>'+title+'</h3>\n'
 
     def chapter_break(self, match):
         chap = match.group('section')
         styles = match.group('styles')
         self.html_preprocess_sections = self.html_preprocess_sections + 1
-        self.log("marked " + str(self.html_preprocess_sections) + " section markers based on punctuation. - " + str(chap))
+        self.log("marked " + unicode(self.html_preprocess_sections) +
+                " section markers based on punctuation. - " + unicode(chap))
         return '<'+styles+' style="page-break-before:always">'+chap
 
     def insert_indent(self, match):
@@ -63,7 +66,8 @@ class PreProcessor(object):
         line_end = line_end_ere.findall(raw)
         tot_htm_ends = len(htm_end)
         tot_ln_fds = len(line_end)
-        self.log("There are " + str(tot_ln_fds) + " total Line feeds, and " + str(tot_htm_ends) + " marked up endings")
+        self.log("There are " + unicode(tot_ln_fds) + " total Line feeds, and " +
+                unicode(tot_htm_ends) + " marked up endings")
 
         if percent > 1:
             percent = 1
@@ -71,7 +75,7 @@ class PreProcessor(object):
             percent = 0
 
         min_lns = tot_ln_fds * percent
-        self.log("There must be fewer than " + str(min_lns) + " unmarked lines to add markup")
+        self.log("There must be fewer than " + unicode(min_lns) + " unmarked lines to add markup")
         if min_lns > tot_htm_ends:
             return True
 
@@ -112,7 +116,7 @@ class PreProcessor(object):
         txtindent = re.compile(ur'<p(?P<formatting>[^>]*)>\s*(?P<span>(<span[^>]*>\s*)+)?\s*(\u00a0){2,}', re.IGNORECASE)
         html = txtindent.sub(self.insert_indent, html)
         if self.found_indents > 1:
-            self.log("replaced "+str(self.found_indents)+ " nbsp indents with inline styles")
+            self.log("replaced "+unicode(self.found_indents)+ " nbsp indents with inline styles")
         # remove remaining non-breaking spaces
         html = re.sub(ur'\u00a0', ' ', html)
         # Get rid of empty <o:p> tags to simplify other processing
@@ -131,7 +135,8 @@ class PreProcessor(object):
         lines = linereg.findall(html)
         blanks_between_paragraphs = False
         if len(lines) > 1:
-            self.log("There are " + str(len(blanklines)) + " blank lines. " + str(float(len(blanklines)) / float(len(lines))) + " percent blank")
+            self.log("There are " + unicode(len(blanklines)) + " blank lines. " +
+                    unicode(float(len(blanklines)) / float(len(lines))) + " percent blank")
             if float(len(blanklines)) / float(len(lines)) > 0.40 and getattr(self.extra_opts,
             'remove_paragraph_spacing', False):
                 self.log("deleting blank lines")
@@ -170,20 +175,20 @@ class PreProcessor(object):
         #print chapter_marker
         heading = re.compile('<h[1-3][^>]*>', re.IGNORECASE)
         self.html_preprocess_sections = len(heading.findall(html))
-        self.log("found " + str(self.html_preprocess_sections) + " pre-existing headings")
+        self.log("found " + unicode(self.html_preprocess_sections) + " pre-existing headings")
         #
         # Start with most typical chapter headings, get more aggressive until one works
         if self.html_preprocess_sections < 10:
             chapdetect = re.compile(r'%s' % chapter_marker, re.IGNORECASE)
             html = chapdetect.sub(self.chapter_head, html)
         if self.html_preprocess_sections < 10:
-            self.log("not enough chapters, only " + str(self.html_preprocess_sections) + ", trying numeric chapters")
+            self.log("not enough chapters, only " + unicode(self.html_preprocess_sections) + ", trying numeric chapters")
             chapter_marker = lookahead+chapter_line_open+chapter_header_open+numeric_chapters+chapter_header_close+chapter_line_close+blank_lines+opt_title_open+title_line_open+title_header_open+default_title+title_header_close+title_line_close+opt_title_close
             chapdetect2 = re.compile(r'%s' % chapter_marker, re.IGNORECASE)
             html = chapdetect2.sub(self.chapter_head, html)
 
         if self.html_preprocess_sections < 10:
-            self.log("not enough chapters, only " + str(self.html_preprocess_sections) + ", trying with uppercase words")
+            self.log("not enough chapters, only " + unicode(self.html_preprocess_sections) + ", trying with uppercase words")
             chapter_marker = lookahead+chapter_line_open+chapter_header_open+uppercase_chapters+chapter_header_close+chapter_line_close+blank_lines+opt_title_open+title_line_open+title_header_open+default_title+title_header_close+title_line_close+opt_title_close
             chapdetect2 = re.compile(r'%s' % chapter_marker,  re.UNICODE)
             html = chapdetect2.sub(self.chapter_head, html)
@@ -207,11 +212,11 @@ class PreProcessor(object):
         # more of the lines break in the same region of the document then unwrapping is required
         docanalysis = DocAnalysis(format, html)
         hardbreaks = docanalysis.line_histogram(.50)
-        self.log("Hard line breaks check returned "+str(hardbreaks))
+        self.log("Hard line breaks check returned "+unicode(hardbreaks))
         # Calculate Length
         unwrap_factor = getattr(self.extra_opts, 'html_unwrap_factor', 0.4)
         length = docanalysis.line_length(unwrap_factor)
-        self.log("*** Median line length is " + str(length) + ", calculated with " + format + " format ***")
+        self.log("*** Median line length is " + unicode(length) + ", calculated with " + format + " format ***")
         # only go through unwrapping code if the histogram shows unwrapping is required or if the user decreased the default unwrap_factor
         if hardbreaks or unwrap_factor < 0.4:
             self.log("Unwrapping required, unwrapping Lines")
@@ -240,7 +245,8 @@ class PreProcessor(object):
 
         # If still no sections after unwrapping mark split points on lines with no punctuation
         if self.html_preprocess_sections < 10:
-            self.log("Looking for more split points based on punctuation, currently have " + str(self.html_preprocess_sections))
+            self.log("Looking for more split points based on punctuation,"
+                    " currently have " + unicode(self.html_preprocess_sections))
             chapdetect3 = re.compile(r'<(?P<styles>(p|div)[^>]*)>\s*(?P<section>(<span[^>]*>)?\s*(<[ibu][^>]*>){0,2}\s*(<span[^>]*>)?\s*(<[ibu][^>]*>){0,2}\s*(<span[^>]*>)?\s*.?(?=[a-z#\-*\s]+<)([a-z#-*]+\s*){1,5}\s*\s*(</span>)?(</[ibu]>){0,2}\s*(</span>)?\s*(</[ibu]>){0,2}\s*(</span>)?\s*</(p|div)>)', re.IGNORECASE)
             html = chapdetect3.sub(self.chapter_break, html)
         # search for places where a first or second level heading is immediately followed by another