Gregor’s luminous, supremely absorbing quest takes place in a strange underground land of giant cockroaches, rideable bats, and violet-eyed humans. When his two-year-old sister Boots tumbles into an air duct in his building’s laundry room, Gregor leaps after her and they fall, à la Alice, into another world. Gregor wants desperately to get home—until he hears that his father, who left Gregor heavy-hearted by disappearing two years ago, may be in Underland himself, kept prisoner by enormous, war-hungry rats. A coalition of creatures and royal humans is formed to rescue him, modeled after an ancient prophetic poem that has foretold Gregor’s arrival and calls him the Overland Warrior. The abiding ache of Gregor’s sadness is matched by his tender care for Boots. Creature depictions are soulful and the plot is riveting; Underland’s dark, cavernous atmosphere is palpable. Explanation and subtlety balance perfectly. Wonderful. (Fiction. 8-12)