Originally Posted by
phessler In iTunes select the book, right-click and select Get Info. Then on the Options tab check the Remember Playback Position box. That should take care of that.
FYI "Remember playback position" is automatically grayed out when the book type is audiobook.
But I did confirm that this only affects mp3 audiobooks and not m4b files.
I conconverted the mp3 audiobook to AAC in iTunes.
I then changed the file extension from m4a to m4b and made sure the book type was set to audiobook.
Now the playback position will be kept no matter what other music I listen to.