This riveting, whip-smart suspense novel by Harrar (First Tiger) follows a philosophy professor under investigation for the disappearance of a teenage cheerleader. Evan Birch gets pulled over by the police one evening on his way home from the supermarket with his 10-year-old twin sons. The police haul him in for interrogation, and he learns that a car much like his was spotted at the park where 16-year-old Joyce Bonner, a local high school student, was working the afternoon she disappeared. He's released after questioning, but damning circumstantial evidence continues to pile up: the police impound Birch's car and find evidence that Bonner was a passenger, leading Birch to remember that he gave several teenagers a ride across campus around the time of the murder. It turns out that the girl had a crush on Birch, and speculation mounts about a possible affair between them, fueled by the handsome professor's habitual flirtatious manner with young women. Birch is coolly bemused as he filters the police questions through the prism of philosophy and falls back on the wisdom of Wittgenstein. His wife, Ellen, treats the dilemma with an icy calm, but eventually even she begins to have doubts, going so far as to question their sons about their park visit during the day of the murder. The interactions between husband, wife and the police detective crackle with sharp dialogue. The result is a first-rate thriller that offers gut-wrenching suspense, ironic humor and a devious, cerebral suspect, with a stunning finale to boot. (Mar.)