diff --git a/src/calibre/ebooks/conversion/utils.py b/src/calibre/ebooks/conversion/utils.py
index 24528d1fb8..6dc3973213 100644
--- a/src/calibre/ebooks/conversion/utils.py
+++ b/src/calibre/ebooks/conversion/utils.py
@@ -316,9 +316,17 @@ class HeuristicProcessor(object):
         '''
         Unwraps lines based on line length and punctuation
         supports a range of html markup and text files
+        
+        the lookahead regex below is meant look for any non-full stop characters - punctuation
+        characters which can be used as a full stop should *not* be added below - e.g. ?!“”. etc
+        the reason for this is to prevent false positive wrapping.  False positives are more
+        difficult to detect than false negatives during a manual review of the doc
+        
+        This function intentionally leaves hyphenated content alone as that is handled by the 
+        dehyphenate routine in a future step
         '''
-        # define the pieces of the regex
 
+        # define the pieces of the regex
         lookahead = "(?<=.{"+str(length)+u"}([a-zäëïöüàèìòùáćéíĺóŕńśúýâêîôûçąężıãõñæøþðßěľščťžňďřů,:)\IA\u00DF]|(?<!\&\w{4});))" # (?<!\&\w{4});) is a semicolon not part of an entity
         em_en_lookahead = "(?<=.{"+str(length)+u"}[\u2013\u2014])"
         soft_hyphen = u"\xad"