If you have audio files that you want to turn into an “audio” book, for convenient listening, the process can be complicated. Luckily, there are some tools out there to accomplish this task.
For $4.99, there is “Audiobook Builder” by Splasm Software. AudioBook Builder Allows you to easily add audio files to a project and select where chapters will go (file break, time break).
So far, I have used it myself to convert multi hour podcast shows to Audiobook Bookmarkable .m4b format. Seems to work great in iTunes and the Music app on iOS. It’s available in the App Store and on their website.