Making her children's book debut, Alvarez (How the Garcia Girls Lost Their Accents) fulfills only some of the potential inherent in her story, which is based on an intriguing legend from the Dominican Republic, where she grew up. The ciguapas are a secret tribe who live underwater "in cool blue caves hung with seashells and seaweed" and venture onto land only at night because they are so afraid of humans. Their unusual anatomy helps preserve their hidden existenceAtheir feet are on backward, so that "when they walked on land, they left footprints going in the opposite directions." But Guapa, an especially beautiful ciguapa, does not fear humans, even after the ciguapa queen warns her that if they capture her, people "will force you to take baths and do laundry and wash your hands before meals." Guapa's curiosity nonetheless drives her to surface from the sea one bright day, whereupon an encounter with a kind boy and his family threatens to ruin the ciguapas' secret. Unfortunately, the narrative is not uniformly focused and the climactic episode lacks tension; the payoff seems small. To a large extent Negrin's (The Selfish Giant) stylized, luminous paintings compensate for the story's shortcomings. Somehow he renders the ciguapas as both elusive and earthy. Portraying the vegetation of the sunlit tropical setting as well as the ciguapas' watery, nocturnal frolics, he suggests a world lush with mystery. Ages 4-7. (Sept.) Copyright 2000 Reed Business Information, Inc.