By John Wray
320 pages; Farrar, Straus, and Giroux
A breathtaking journey through the subway tunnels of Manhattan and the subterranean fantasies of a schizophrenic teen, the eponymous Lowboy careens toward disaster as the boy, a.k.a. Will Heller, disappears into the urban netherland. A wary detective gives chase, along with "Violet," a mother who harbors disturbing secrets about her son. Lowboy has an apocalyptic obsession with global warming (he believes that only he can save the world), but more immediate perils reside in the twists and turns of the human psyche.