Stuck on Earth

Ketchvar, a snail-like organism, has spent most of his two thousand years in the comfortable ooze of his home planet, Sandavol IV. But Sandavol IV is dying, and he's now on a mission to find a suitable home for his people. Scientific data indicate that Earth will do, but in order for his species to colonize it, all humans would have to be eliminated. His mission: to study the planet and determine the worthiness of its inhabitants. Ketchvar will make his observations by inhabiting the brain of an Earthling; by random choice, he selects Tom Filber, a fourteen-year-old bullied boy with a miserable home- and social life. Ketchvar's speech ("Greetings, sister...I come in peace") is formal and his thinking humorously literal. When, for instance, he goes to find Tom's alcoholic father at the local bar, Ketchvar assumes Mr. Filber is "involved in a religious ritual" when told he is "paying his respects to the marble altar." Many of his observations, however, reflect uncomfortable truths, such as cliquish teen cruelty and the existence of toxic waste dumps. Klass's novel, with its twists and turns and many changes of setting, may lose those wishing for more character development but hit the spot for plot-driven readers. BETTY CARTER