Convert an mp3 into an audiobook in iTunes 12

Convert a long mp3 into an audiobook so your device can keep track of where you are. These instructions are tested with iTunes 12.6.1.25.

1. Right click the mp3 in iTunes > Get info.
   
2. Select the "Options" tab.
3. Change "media kind" from "Music" to "Audiobook". Make sure "Remember playback position" and "Skip when shuffling" are checked.
4. Select the "Details" tab.
   
5. Change the fields "title" and "author". The "chapter" field can have the same value as "title".
6. Click OK.
7. Drag the audiobook to your iPhone or iPad. (optional)

Audiobooks appear in the iBooks app on the iPhone whereas podcasts appear in the Podcast app.