This charming picture book explores how various animals sleep. Each double page provides one line of loosely rhyming text framed in a wide pale yellow border, and a full-color photograph of a particular animal also framed in soothing yellow. Among the animals are the horse, chipmunk, bear, sloth, koala, bat, and shark. The photographs are clear and appealing, but sharp-eyed viewers will notice that a couple of the animals are not sleeping, no matter what the text says. Kajikawa concludes with additional information on the sleep habits of animals. Some information is not consistent with that reported by other science writers, e.g., on the sleeping habits of horses, but this remains an appealing book on a subject that fascinates children. (Picture book/nonfiction. 4-6)