I used to love reading these to my now 14 year old when he was little.
The humor in them is HILARIOUS; Frank Baum is a genius, and the illustrations are the Bomb. These are a whole different world from the movie and even more amazing in my opinion. And now I have found them on audio on youtube!
Ideal for listening to with your little ones as they fall asleep at night!

Audio Version: The Wonderful Wizard of Oz by Frank Baum

List of the books in order