Both deleted and new audiobooks show in iTunes, but not on iPhone Today I


finished an audiobook;
deleted the book from the iphone (i.e., did not do anything in iTunes)
used iTunes (PC) to transfer a new book to the iphone.


Neither of the books shows on the iphone, but both do show in iTunes. The new book is greyed out with dotted circles next to the chapters; the deleted book is in black.

This is an iphone X running ios 11.3.1, and has plenty of storage (50GB).

What steps do I need to take to truly delete the old book and to be able to see the new book on the iphone? (Specific steps appreciated, vs. generalizations.)
Found some old (iphone 8) information that suggested it's a syncing problem related to manual syncing, and led me to figure out this answer for the iphone X.


Disconnect iPhone from iTunes.
In iTunes, delete the unwanted book from the library and move it to the recycle bin. (Note: This step might not be necessary, but I did it as an extra precaution/preemptive step. If I wanted to keep the book, then I'd just have to remember to retrieve it from the recycle bin.) 
Still in iTunes, go to Edit > Preferences > Devices
Uncheck "Prevent...from syncing automatically"
Reset Sync History
Click OK.
Reconnect iPhone to iTunes. Wait for the synching process to complete.
In iTunes, edit preferences to manually sync again (assuming this is the state you want to revert to).


Note: I was nervous about auto syncing because I thought it might transfer all music and all audiobooks to the phone, which I definitely did not want. Am happy to report that in this case, the only audiobook synched to the phone was the one I'd already transferred.