diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index ad5b040e68..05b624f811 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -249,7 +249,7 @@ class MetaInformation(object):
         ans = u''
         ans += u'Title    : ' + unicode(self.title) + u'\n'
         if self.authors:
-            ans += u'Author   : ' + (', '.join(self.authors) if self.authors is not None else u'None')
+            ans += u'Author   : ' + (' & '.join(self.authors) if self.authors is not None else _('Unknown'))
             ans += ((' [' + self.author_sort + ']') if self.author_sort else '') + u'\n'
         if self.publisher:
             ans += u'Publisher: '+ unicode(self.publisher) + u'\n'
diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index 31b9ef99b3..63ef7b0b14 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -33,7 +33,7 @@ class EXTHHeader(object):
         self.length, self.num_items = struct.unpack('>LL', raw[4:12])
         raw = raw[12:]
         pos = 0
-        self.mi = MetaInformation('Unknown', ['Unknown'])
+        self.mi = MetaInformation(_('Unknown'), [_('Unknown')])
         self.has_fake_cover = True
         
         for i in range(self.num_items):
@@ -63,7 +63,9 @@ class EXTHHeader(object):
                 
     def process_metadata(self, id, content, codec):
         if id == 100:
-            self.mi.authors   = [content.decode(codec, 'ignore').strip()]
+            if self.mi.authors == [_('Unknown')]:
+                self.mi.authors = []
+            self.mi.authors.append(content.decode(codec, 'ignore').strip())
         elif id == 101:
             self.mi.publisher = content.decode(codec, 'ignore').strip()
         elif id == 103: