Beneath its veneer of affluence and respectability, Kellerman's Los Angeles is a cesspool of corruption and lies where ''savagery reigns.'' In other words, it's the perfect milieu for psychologist/police consultant Alex Delaware (in his 18th mystery) and world-weary detective Milo Sturgis to investigate four gruesome murders -- several victims have been impaled -- all seemingly connected to a popular Beverly Hills psychotherapy practice. The savvy duo confronts an array of sleazy characters, and their analysis of each suspect's possible motive is often fascinating. That attention to detail also makes Therapy occasionally tedious. The suspense gets bogged down with Alex constantly mired in L.A. traffic jams (''Cars were queued up at the 101 on-ramp, so I took Olympic Boulevard, west''). Still, it's a moderately entertaining thriller and not a bad way to pass the time while idling on your commute.