BRIEFLY NOTED.

Steven Shapin on Steven Johnson's "The Ghost Map."

John Updike on "Uncle Tom's Cabin."

Elizabeth Kolbert on the Armenian genocide and the politics of silence.

The Echo Maker, by Richard Powers (Farrar, Straus & Giroux; $25). This novel, a finalist for the National Book Award, addresses the question of how we know who we really are. Mark, who repairs machinery at a meat-processing plant, suffers a head injury that prevents him from recognizing his sister Karin; he believes that she is a look-alike sent to spy on him. Karin, who has spent her life trying to escape their small Nebraska town, returns to old lovers and habits she thought she'd renounced. Stung by Mark's rejection, she sends a desperate plea to an Oliver Sacks-like neurologist whose popular books have suddenly come under critical attack, causing fissures in his public persona and his seemingly perfect marriage. Powers's smooth coincidences and cute patter can be unconvincing and leaden, and he has a tendency to lapse into distracting repetitions. Yet his philosophical musings have the energy of a thriller, and he gives lyrical, haunting life to the landscape of the Great Plains.

The Uses of Enchantment, by Heidi Julavits (Doubleday; $24.95). The author's third novel is a spooky coming-of-age tale set in West Salem, Massachusetts, a town whose witch-hanging history both captivates and circumscribes the lives of the teen-age girls who reside there. One afternoon in 1985, sixteen-year-old Mary Veal disappears from field-hockey practice at the austere Semmering Academy; she reappears a few weeks later claiming to have been abducted. The truth of what happened is only hinted at in Mary's sexually charged experiences with her supposed captor and in her provocative exchanges with the therapist assigned to her case. He decides that Mary is lying--aspects of her story seem taken from a previous student's faked abduction, itself inspired by a centuries-old fable involving a kidnapped girl and witchcraft--but, it ...