Escape from Mr. Lemoncello’s Library by Chris Grabenstein
I can easily understand why my 4th grade students have raved about this one: there’s the thrill of watching a complex puzzle being solved, the excitement of exploring new friendship, the coziness of strengthening old friendship, and the novelty of discovering inventions of a high-tech, but still story-filled, library. Plus a little bit of safe scare: facing down and defeating villains that really aren’t that threatening from beginning to end. This is old school children’s mystery fun.