It is a disconcerting fact that the world’s most infamous “mass murderer” did not physically kill the people for whose deaths he is usually held responsible. Charles Manson, subject of a well-researched new biography by Jeff Guinn, was at worst the orchestrator of the Tate-LaBianca massacres of August 1969, not the perpetrator. When Guinn describes how the arch-opportunist Manson recruited Charles “Tex” Watson to lead the rampages – it was Watson who performed most of the atrocity, including the exsanguination of Sharon Tate – he explains, “[Manson] manipulated Tex so neatly that later on, when Tex claimed that Charlie ordered him to commit the murders and Charlie swore that they were Tex’s and the Family’s idea, not his, both of them were telling a version of the truth.”

For the millions perversely fascinated by Manson, Guinn’s book doesn’t actually reveal much that hasn’t been told in Vincent Bugliosi and Curt Gentry’s Helter Skelter and elsewhere. But by unfolding Manson’s life story in chronological order, from his ancestry, childhood, and rotating-door incarcerations of youth onward, to the ominous months and weeks following his last parole in March 1967, Guinn paints an effective picture of “the wrong man in the right place at the right time.” Manson was not, at bottom, a monstrous lunatic, but a con artist with a pimp’s instincts for exploiting women, who was quite literally turned loose on the impressionable hippies of Haight-Ashbury during the Summer of Love.

Perhaps the most original angle here is the depiction of the Tate-LaBianca slayings not as Manson’s coldly calculated bid to precipitate Helter Skelter – an apocalyptic race war from which he and his followers would emerge triumphant – but rather as the expedient, almost desperate moves of a career criminal facing a quick return to jail. Manson associate Bobby Beausoleil had already been arrested for the murder of Gary Hinman; Manson had shot and thought he had killed an African-American drug dealer who claimed ties to the Black Panthers paramilitary group; Manson’s longstanding ambition of rock stardom had come to nought after brush-offs by industry insiders Terry Melcher and Dennis Wilson; sooner or later, he worried, he’d lose the adoration of the Family and earn the attention of the police (for his ties to Beausoleil and the Hinman killing) and the Black Panthers (for his attack on the dealer and for his racist paranoia). The savage raids of August 9 and 10 were dreamed up on the fly, partly to exonerate Beausoleil by suggesting Hinman’s murderer was still at large and leaving bloody messages, and partly to incite civil unrest by implicating a Black Panthers-type group that was assaulting wealthy whites in their homes. What we think of today as the gory climax of a messianic delusion was more a violent sequence of gambles and improvisations conducted by a clueless gang of stoned dropouts.

The Manson legend was enormously enhanced by the success of Helter Skelter in 1974; co-author Bugliosi, of course, had prosecuted Manson and three of the other killers and perhaps had a vested interest in embellishing Manson into an evil mastermind. There was also the Helter Skelter TV miniseries of 1976, in which Steve Railsback’s performance was so compelling as to become the standard public image of Manson himself (his courtroom monologue is one of the most powerful pieces of acting you’re likely to see). Ultimately, though, it’s that star-crossed coincidence of social turmoil, drug-addled gullibility, and the magnetism of a single hardened sociopath that makes the Manson tale so tragic, for both its dead and living casualties. In one of the biography’s most poignant moments, Jeff Guinn tells of the eighteen-year-old future murderess Leslie Van Houten in 1968, estranged from her middle-class family, inadvertently stranded by her new friends Bobby Beausoleil and two other Manson Family girls before they returned to bring her on their fateful ride together. “Leslie waited for almost fifteen minutes, wondering if they were going to come back and, as the minutes passed, thinking that maybe this was an omen, maybe she should stay behind in the Haight or even go home…[I]t had been a near thing, and afterward Leslie wondered how different her life might have been.” Hers and a lot of other people’s.