diff --git a/beets/importer.py b/beets/importer.py
index 94594a2a2..4af276abe 100644
--- a/beets/importer.py
+++ b/beets/importer.py
@@ -1365,8 +1365,13 @@ def user_query(session, task):
                                 user_query(session))
 
     resolve_duplicates(session, task)
+
     if task.should_merge_duplicates:
+        # Create a new task for tagging the current items
+        # and duplicates together
         duplicate_items = task.duplicate_items(session.lib)
+
+        # duplicates would be reimported so make them look "fresh"
         _freshen_items(duplicate_items)
         duplicate_paths = [item.path for item in duplicate_items]
 
diff --git a/docs/guides/tagger.rst b/docs/guides/tagger.rst
index 4c9df42f8..db11dbcc6 100644
--- a/docs/guides/tagger.rst
+++ b/docs/guides/tagger.rst
@@ -234,17 +234,25 @@ If beets finds an album or item in your library that seems to be the same as the
 one you're importing, you may see a prompt like this::
 
     This album is already in the library!
-    [S]kip new, Keep both, Remove old?
+    [S]kip new, Keep both, Remove old, Merge all?
 
 Beets wants to keep you safe from duplicates, which can be a real pain, so you
-have three choices in this situation. You can skip importing the new music,
+have four choices in this situation. You can skip importing the new music,
 choosing to keep the stuff you already have in your library; you can keep both
-the old and the new music; or you can remove the existing music and choose the
-new stuff. If you choose that last "trump" option, any duplicates will be
+the old and the new music; you can remove the existing music and choose the
+new stuff; or you can merge the newly imported album and existing duplicate
+into one single album. 
+If you choose that "remove" option, any duplicates will be
 removed from your library database---and, if the corresponding files are located
 inside of your beets library directory, the files themselves will be deleted as
 well.
 
+If you choose "merge", beets will try re-importing the existing and new tracks
+as one bundle so they will get tagged together appropriately.
+This is particularly helpful when you are importing extra tracks
+of an album in your library with missing tracks, so beets will ask you the same
+questions as it would if you were importing all tracks at once.
+
 If you choose to keep two identically-named albums, beets can avoid storing both
 in the same directory. See :ref:`aunique` for details.
 
diff --git a/docs/reference/config.rst b/docs/reference/config.rst
index 9faddd2d2..ce45a94ee 100644
--- a/docs/reference/config.rst
+++ b/docs/reference/config.rst
@@ -571,11 +571,12 @@ Default: ``yes``.
 duplicate_action
 ~~~~~~~~~~~~~~~~
 
-Either ``skip``, ``keep``, ``remove``, or ``ask``. Controls how duplicates
-are treated in import task. "skip" means that new item(album or track) will be
-skipped; "keep" means keep both old and new items; "remove" means remove old
-item; "ask" means the user should be prompted for the action each time.
-The default is ``ask``.
+Either ``skip``, ``keep``, ``remove``, ``merge`` or ``ask``. 
+Controls how duplicates are treated in import task. 
+"skip" means that new item(album or track) will be skipped; 
+"keep" means keep both old and new items; "remove" means remove old
+item; "merge" means merge into one album; "ask" means the user 
+should be prompted for the action each time. The default is ``ask``.
 
 .. _bell: