I very nearly gave this a “recommended.”  The riddles are generally quite clever (all school themed, as the title indicates), and these types of play on words are good for developing children’s vocabulary.  The reason I hesitate is based on bang for one’s library buck — given the cost of reinforced library binding, I’d like to see more than 20 jokes in the entire book — but if you can afford it, it is a fun book.  I do however disagree with the publisher’s target audience.  They list it with a reading level of K-1 and an interest level of PreK-2.  Though preschoolers do tend to show an interest in the concept of riddles, they rarely “get” them, and it would take a very advanced kindergartener to read this.  I would suggest it for grades 2-5.