Melinda writes in and asks,
"I am using the latest version of iTunes and all of a sudden, my audio books and radio are missing from the sidebar in iTunes'. I don't know how to fix it."
I think what has happened is you've unchecked some options in the iTunes Sidebar.
Let's fix it:
1. In the iTunes menu, choose 'Preferences'.
2. Click on the 'General' tab if it isn't already selected. You will see several options under the 'Show' section. Simply add check-marks next to items you want to see in your sidebar Library. Uncheck items you don't want to see. This won't delete them, it simply unclutters your sidebar.
3. Now you should see the options you've chosen in the iTunes Library sidebar.