AudioBooks - Settings not appearing in iTunes

For several years I used my iPod Touch regularly to listen to audiobooks. But I got out of the habit, and cleared the books from my iPod.

Now I want to transfer books to the device again. I know all of my books are still in my iTunes library inside iTunes Media, but there is not entry for AudioBooks in the Settings list of iTunes. Without that I can't transfer my books over to the iPod.

Help?