diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index 9150172fc1..92a68fa840 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -50,6 +50,7 @@ gprefs.defaults['action-layout-context-menu-device'] = (
 
 gprefs.defaults['show_splash_screen'] = True
 gprefs.defaults['toolbar_icon_size'] = 'medium'
+gprefs.defaults['automerge'] = 'ignore'
 gprefs.defaults['toolbar_text'] = 'auto'
 gprefs.defaults['show_child_bar'] = False
 gprefs.defaults['font'] = None
diff --git a/src/calibre/gui2/actions/add.py b/src/calibre/gui2/actions/add.py
index 4236a63340..25127d3635 100644
--- a/src/calibre/gui2/actions/add.py
+++ b/src/calibre/gui2/actions/add.py
@@ -244,8 +244,8 @@ class AddAction(InterfaceAction):
                     x.decode(preferred_encoding, 'replace') for x in
                     self._adder.merged_books])
             info_dialog(self.gui, _('Merged some books'),
-                    _('Some duplicates were found and merged into the '
-                        'following existing books:'), det_msg=books, show=True)
+                    _('The following duplicate books were found and incoming book formats were '
+                        'processed and merged into your Calibre database according to your automerge settings:'), det_msg=books, show=True)
         if getattr(self._adder, 'critical', None):
             det_msg = []
             for name, log in self._adder.critical.items():
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index 026fabea07..086f40feee 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -8,7 +8,7 @@ from functools import partial
 from PyQt4.Qt import QThread, QObject, Qt, QProgressDialog, pyqtSignal, QTimer
 
 from calibre.gui2.dialogs.progress import ProgressDialog
-from calibre.gui2 import question_dialog, error_dialog, info_dialog
+from calibre.gui2 import question_dialog, error_dialog, info_dialog, gprefs
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.ebooks.metadata import MetaInformation
 from calibre.constants import preferred_encoding, filesystem_encoding, DEBUG
@@ -179,23 +179,46 @@ class DBAdder(QObject): # {{{
                     cover = f.read()
             orig_formats = formats
             formats = [f for f in formats if not f.lower().endswith('.opf')]
-            if prefs['add_formats_to_existing']:
+            if prefs['add_formats_to_existing']: #automerge is on
                 identical_book_list = self.db.find_identical_books(mi)
-
-                if identical_book_list: # books with same author and nearly same title exist in db
+                if identical_book_list:  # books with same author and nearly same title exist in db
                     self.merged_books.add(mi.title)
+                    a_new_record_has_been_created = False
                     for identical_book in identical_book_list:
-                        self.add_formats(identical_book, formats, replace=False)
-                else:
-                    id = self.db.create_book_entry(mi, cover=cover, add_duplicates=True)
+                        if gprefs['automerge'] == 'ignore':
+                            self.add_formats(identical_book, formats, replace=False)
+                        if gprefs['automerge'] == 'overwrite':
+                            self.add_formats(identical_book, formats, replace=True)
+                        if gprefs['automerge'] == 'new record' and not a_new_record_has_been_created:
+                            '''
+                            We are here because we have at least one book record in the db that matches the one file/format being processed
+                            We need to check if the file/format being processed matches a format in the matching book record.
+                            If so, create new record (as below), else, add to existing record, as above.
+                            Test if format exists in matching record. identical_book is an id, formats is a FQPN path in a list
+                            '''
+                            for path in formats:
+                                fmt = os.path.splitext(path)[-1].replace('.', '').upper()
+                                ib_fmts = self.db.formats(identical_book, index_is_id=True)
+                                if ib_fmts and fmt in ib_fmts: # Create a new record
+                                    if not a_new_record_has_been_created:
+                                        id_ = self.db.create_book_entry(mi, cover=cover, add_duplicates=True)
+                                        self.number_of_books_added += 1
+                                        self.add_formats(id_, formats)
+                                        a_new_record_has_been_created = True
+                                else: #new record not required
+                                    self.add_formats(identical_book, formats, replace=False)
+
+                else: # books with same author and nearly same title do not exist in db
+                    id_ = self.db.create_book_entry(mi, cover=cover, add_duplicates=True)
                     self.number_of_books_added += 1
-                    self.add_formats(id, formats)
-            else:
-                id = self.db.create_book_entry(mi, cover=cover, add_duplicates=False)
-                if id is None:
+                    self.add_formats(id_, formats)
+
+            else: #automerge is off
+                id_ = self.db.create_book_entry(mi, cover=cover, add_duplicates=False)
+                if id_ is None:
                     self.duplicates.append((mi, cover, orig_formats))
                 else:
-                    self.add_formats(id, formats)
+                    self.add_formats(id_, formats)
                     self.number_of_books_added += 1
         else:
             self.names.append(name)
diff --git a/src/calibre/gui2/preferences/adding.py b/src/calibre/gui2/preferences/adding.py
index e919d53b64..b4c4ce846a 100644
--- a/src/calibre/gui2/preferences/adding.py
+++ b/src/calibre/gui2/preferences/adding.py
@@ -12,6 +12,7 @@ from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
 from calibre.gui2.preferences.adding_ui import Ui_Form
 from calibre.utils.config import prefs
 from calibre.gui2.widgets import FilenamePattern
+from calibre.gui2 import gprefs
 
 class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
@@ -23,18 +24,23 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         r('read_file_metadata', prefs)
         r('swap_author_names', prefs)
         r('add_formats_to_existing', prefs)
+        choices = [
+                (_('Ignore duplicate incoming formats'), 'ignore'),
+                (_('Overwrite existing duplicate formats'), 'overwrite'),
+                (_('Create new record for each duplicate format'), 'new record')]
+        r('automerge', gprefs, choices=choices)
         r('new_book_tags', prefs, setting=CommaSeparatedList)
 
         self.filename_pattern = FilenamePattern(self)
         self.metadata_box.layout().insertWidget(0, self.filename_pattern)
         self.filename_pattern.changed_signal.connect(self.changed_signal.emit)
 
-
     def initialize(self):
         ConfigWidgetBase.initialize(self)
         self.filename_pattern.blockSignals(True)
         self.filename_pattern.initialize()
         self.filename_pattern.blockSignals(False)
+        self.opt_automerge.setEnabled(self.opt_add_formats_to_existing.isChecked())
 
     def restore_defaults(self):
         ConfigWidgetBase.restore_defaults(self)
diff --git a/src/calibre/gui2/preferences/adding.ui b/src/calibre/gui2/preferences/adding.ui
index 75e6c466f0..f9a2c74444 100644
--- a/src/calibre/gui2/preferences/adding.ui
+++ b/src/calibre/gui2/preferences/adding.ui
@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>750</width>
+    <width>753</width>
     <height>339</height>
    </rect>
   </property>
@@ -58,16 +58,33 @@
      </item>
     </layout>
    </item>
-   <item row="2" column="0" colspan="2">
+   <item row="2" column="0">
     <widget class="QCheckBox" name="opt_add_formats_to_existing">
      <property name="toolTip">
-      <string>If an existing book with a similar title and author is found that does not have the format being added, the format is added
-to the existing book, instead of creating a new entry. If the existing book already has the format, then it is silently ignored.
+      <string>Automerge: If books with similar titles and authors found, merge the incoming formats automatically into
+existing book records. The box to the right controls what happens when an existing record already has
+the incoming format. Note that this option also affects the Copy to library action.
 
 Title match ignores leading indefinite articles (&quot;the&quot;, &quot;a&quot;, &quot;an&quot;), punctuation, case, etc. Author match is exact.</string>
      </property>
      <property name="text">
-      <string>If books with similar titles and authors found, &amp;merge the new files automatically</string>
+      <string>&amp;Automerge added books if they already exist in the calibre library:</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="1">
+    <widget class="QComboBox" name="opt_automerge">
+     <property name="toolTip">
+      <string>Automerge: If books with similar titles and authors found, merge the incoming formats automatically into
+existing book records. This box controls what happens when an existing record already has
+the incoming format: 
+
+Ignore duplicate incoming files - means that existing files in your calibre library will not be replaced
+Overwrite existing duplicate files - means that existing files in your calibre library will be replaced
+Create new record for each duplicate file - means that a new book entry will be created for each duplicate file
+
+Title matching ignores leading indefinite articles (&quot;the&quot;, &quot;a&quot;, &quot;an&quot;), punctuation, case, etc.
+Author matching is exact.</string>
      </property>
     </widget>
    </item>
@@ -113,5 +130,22 @@ Title match ignores leading indefinite articles (&quot;the&quot;, &quot;a&quot;,
   </layout>
  </widget>
  <resources/>
- <connections/>
+ <connections>
+  <connection>
+   <sender>opt_add_formats_to_existing</sender>
+   <signal>toggled(bool)</signal>
+   <receiver>opt_automerge</receiver>
+   <slot>setEnabled(bool)</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>406</x>
+     <y>83</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>457</x>
+     <y>83</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
 </ui>
diff --git a/src/calibre/library/server/content.py b/src/calibre/library/server/content.py
index 62d08aa2c3..11ea2b951e 100644
--- a/src/calibre/library/server/content.py
+++ b/src/calibre/library/server/content.py
@@ -124,7 +124,6 @@ class ContentServer(object):
             cherrypy.request.headers.get('Want-OPDS-Catalog', 919) != 919 or \
             ua.startswith('Stanza')
 
-        # A better search would be great
         want_mobile = self.is_mobile_browser(ua)
         if self.opts.develop and not want_mobile:
             cherrypy.log('User agent: '+ua)