OK. So the subject says it all. This may be true on the Mac as well, but I don't know that for sure. I know it is true on windows. I am using iTunes 18.104.22.168. I just updated it a few minutes ago before this post. I went to try to sink an MP3 Audio book to my iTunes Library. Then I highlighted it and did a control+I to edit multiple song information. To kill multiple birds with one stone if you will. This is not music, this is an audio book but it puts it in my music. That's fine until the following. I chose options within the get info dialog and chose audio book for the media kind. I hit OK, and the audio book does not move out of the music category. I did a sink with to my iPhone and it still didn't work. Even worse, I can't delete the audio book from my iTunes Library. There is no option to delete what so ever. Since it is in my music app, I tried deleting it from the iPhone and it won't let me delete. Please help if anyone else is having this problem.