Betty G. Birney, . . Putnam, $14.99 (160pp) ISBN 978-0-399-24198-7

"You can learn a lot if you stop spinning and start listening." Such is the deep moral for this breezy, well-crafted first novel, narrated by a hamster purchased by a substitute teacher for a middle-school classroom. Humphrey's heart feels broken when the substitute's stint is up ("I'm never going to squeak to her again," he laments)—and it doesn't help that the regular teacher hates "rodents." But the class parents and the Most Important Person at Longfellow School (the principal) hatch a plan: a different student will take Humphrey home each weekend. "It's a wonderful way to teach the kids responsibility," enthuses one mother, but Humphrey has his own ideas, believing it is up to him to help solve "his" students' problems. This cheerful set-up leads to a succession of sweet-natured encounters. For example, a stay with "Speak-Up-Sayeh" prompts the shy girl, who worries that others will laugh at her accent, to get her family to finally attempt some English ("No wonder Sayeh got 100% on all her vocabulary tests," says Humphrey with comic naïveté when he hears them speaking a foreign language. "She and her family knew a lot more words than I did"). Humphrey's matter-of-fact, table-level view of the world is alternately silly and profound, and Birney (Tyrannosaurus Tex ) captures his unique blend of innocence and earnestness from the start. Given the perky protagonist and chipper delivery, middle-grade readers are sure to savor this classroom caper. Ages 7-up. (Feb.)