Amazon is offering their Cat in the Hat Learning Library books for only $4.15 each, regularly $9.99!! These books are some of the best at explaining concepts in a fun and adventurous way. We have only borrowed them from the library, but I'm buying a bunch of these today to build up our home library. My four-year old loves to read these and she feels so smart after because she can explain how things work or tell you all the facts about an animal or bug. Remember that Amazon is subject to change prices at any time, so get them while they are hot.