A hefty recap of the two-year existence of the ""Symbionese Liberation Army"" and its 1974 kidnapping of Patty Hearst. What was the SLA? Was Hearst brainwashed or voluntarily converted to terrorism? On the second question, the authors conclude that she certainly underwent drastic psychological coercion, a topic oddly botched by her legal defense. On the first question, the book mentions the exposure of key SLA people to behavior modification and radical political indoctrination in the California prisons--from which some of them escaped with great ease. McLellan and Avery also cite the group's connections with intelligence-agency figures like Colston Westbrook, but minimize this angle as intra-""left"" backbiting. Essentially, they approach the SLA as a weird yet organic outgrowth of the New Left: ""Perhaps it was an inevitable marriage of Charles Manson's insane dune-buggy fascism and the arrogant proto-Marxism of the early Weathermen."" Combined with these sociological speculations are biographies of the terrorists--nothing major that hasn't been in the press--and itemizations of who slept with whom at any given moment Sources remain unnamed. There are also interesting profiles of Hearst's fiance Stephen Weed, a cynical Republican despite the scruffy exterior that made Patty's parents call him ""Toothbrush"" behind his back--and of the parents themselves, loosestrung Randolph and his militant wife. The final effect of the book is to make this ""bizarre chapter"" seem one more excretion of a decadent age. Dramatic, yes; deftnitive, no.