Comment 3 for bug 1081096

Here you go
As you can see, the synch returns many files of type AAC audio file. I assume MP3s have the same problem, both caused by the "loose" interpretation of "books" by iTunes.

An example of a book that causes a problem:
The Bodies Left Behind, by Jeffery Deaver - Even when the eBook is not in iTunes, calibre reports that it is, because it picks up the audiobook.
You can also see this when you go to the Device view in calibre - calibre shows audiobooks in the list, instead of just ebooks.

Thomas