After writing five mystery thrillers as Keith Peterson (The Scarred Man, 1989), Klavan at last puts his real name on one-and no wonder: this take of a psychiatrist trying to save his kidnapped daughter is a virtuoso display of Chinese puzzle-box plotting and slick emotionality, worthy of Hitchcock at his best. ``The right apartment was tough to find, so they murdered the old lady,''-sociopath Sport and his monster-sized retarded sidekick Maxwell, that is, setting up in this opening sentence their rental of the suddenly vacant apartment across the yard from the one owned by mild-mannered shrink Nathan Conrad, wife Agatha, and five-year-old daughter Jessica. The Conrads become aware of Sport and Maxwell when they awake one day to find their apartment broken into, Jessica snatched, and Sport on the phone. The ransom? Nathan must visit Elizabeth Burrows, the paranoid angel-faced murderess he's treating at the request of fellow shrink Jerry Sachs, and ask her, ``What is the number?'' and ``don't say a word'' to the cops, warns Sport, whose surveillance of the Conrads through binoculars convinces the couple that they're being watched by hidden cameras and microphones-a lie that cuffs Agatha as she tries to call for help from a neighbor and a plumber: Or is one of these men Sport in disguise? Meanwhile, Nathan dashes to the asylum, confronts Sachs, and visits fragile Elizabeth, discovering, as twist follows twist, that her paranoia is based on a hideous reality. Breaking her out, Nathan races with Elizabeth to a rendezvous with Sport (be at the clocktower by 9:00 p.m. or Jessica dies) as she reveals ``the number''-key to a fateful secret. But even after Nathan settles with Sport, can he-as asked in an extended and astonishingly cathartic climax-find Jessica in time to keep monstrous Maxwell from tearing the little girl apart limb by limb? Not profound, and blatant in its emotional manipulations, but peopled with rich characters and intensely gripping and suspenseful: one of the most entertaining psychothrillers in many months.