Thanks, Buckey_Reader. I've seen those instructions before, but this:
Originally Posted by Buckeye_Reader
Please note that WMA audiobooks will not be listed in 'Audiobooks' on your iOS device.
is the problem that needs solving (by Overdrive or iTunes, or both).
That said, sometimes some parts of the audiobooks DO appear in audiobooks of their own accord. And sometimes you can make the other parts go there simply by changing something in "Get Info" (for example adding the total number of parts in the "Track <#> of <#> field). And sometimes nothing works, they only appear in playlists, and you have to do this instead: https://discussions.apple.com/message/17583410#17583410
Anyway, I'll try downloading the Overdrive PC software again. The "check for updates" never says there is anything available...