Cummings brings Harvey Moon back after far too long an absence. This time, he’s going to the museum with his class (and his pet lizard, Zippy, in his backpack). Unfortunately, early in the day, Zippy is startled by the excited noise made by Harvey’s classmates at the museum. After many near-captures, and several funny pages of the chaos Zippy causes, Harvey catches him and decides to lay low for a while. Before he knows it, the museum is closed. Suddenly, the artwork comes to life with charging knights, walking mummies and flying pterodactyls. After another chase through the museum, Harvey and Zippy make it out okay. In an abrupt transition, there are reporters, his parents and schoolmates waiting outside, all happy to find the missing Harvey. The final page offers a humorous ending that’s likely to be found amusing only by adults. The illustrations are the strength here: Cummings uses lots of color and humor while cleverly showing the relationships between the museum contents and Harvey’s tale. (Picture book. 3-6)