Ken Bianchi was ""a gentle, friendly young man, eager to help anyone in trouble,"" a steady worker, a good mate, the devoted father of a newborn son. He was also, by his own admission, the ""Hillside Strangler,"" who murdered a dozen young women in Los Angeles during the 1977-78 winter and two more in Bellingham, Washington, before he was caught. Schwartz works backward, starting with the 1979 Washington murders and the painstaking local police investigation that quickly zeroed in on Bianchi--whose arrival coincided with the end of the L.A. killings. Bianchi was totally bewildered--he figured he'd been wronged by circumstances. From the arrest, Schwartz backpeddles to the series of Hillside Strangler murders: the sleazy, street-life side of Hollywood and its runaways, pimps, and junkies; a city increasingly gripped by panic; the suspicion that the killer might be a policeman (one investigative sidelight was the discovery of a dozen or so ""fake police""); deranged compulsive confessors, including one actor whose career was irremediably damaged by the resulting bad press. Meanwhile, Schwartz tracks the daily lives of Kelli and Ken, a reasonably average, rootless young L.A. couple. At first Kelli thought Ken was very close to being Mr. Right, but there were some problems: he was immature, reckless with money, spent too much time with his cousin (an older man on the fringe of the Hollywood street scene), and went in for grandiose schemes, like becoming a psychological counselor. After Ken's arrest, it all started to Come clear under hypnosis: Ken was, at the very least, two people--nonaggressive Ken, and vicious, foulmouthed, murderous Steve--a textbook multiple personality. Ken/Steve confessed to the homicides, and implicated his cousin. But the police investigators were never totally convinced of Bianchi's split personality. He had a small library of psychology books, and the police felt that the psychiatrists ""treating"" him were unwittingly educating him in how to pull off a con. Schwartz' marshalling of the psychiatric evidence suggests, however, that Bianchi wasn't posing. And, once Bianchi began to understand what he'd done, Schwartz indicates, he couldn't face it. Result: Bianchi confessed, pleaded guilty, but retreated so far from reality that the likelihood of his testifying credibly against his alleged accomplice was nil. Straightforward, understated, and creepy: a very fine job.