Burrows, a former journalist, scrutinizes a score of vigilante outbreaks in America's 200-year history in an attempt to understand what triggers ""respectable"" citizens--and they are usually pillars of the community--to take the law into their own hands. His investigations range from the South Carolina ""Regulators"" of the 1760s to the 6000-strong Committee of Vigilance operating in San Francisco in the 1850s and the ad hoc New Orleans citizens group which sprang up to avenge the murder of a police chief by--it was believed--Sicilian ""mafia"" in the 1890s. Dramatically presented, Burrows' case histories illustrate the moral and legal ambiguities of vigilante organizations; the author candidly announces that the potential for such groups exists in every community. Characteristically they profess to work for the benefit of the community; in the words of the South Carolina Regulators: ""to defend our Families, by our own Strength: As Legal Methods are beyond our Reach."" (In this particular instance, Burrows feels the claim was justified.) While shying away from absolutist definitions of vigilantism, Burrows excludes the Ku Klux Klan, the Jewish Defense League, and the Black Panthers on the grounds of longevity and continuity. He argues that the true vigilante group forms to combat or avenge specific, immediate dangers. Once this goal is achieved, the organization may degenerate: starting as the defenders of life and property the vigilantes may become bullies, self-appointed extirpators of gambling, drunkenness, or wife-beating. A sobering, engrossing study of how violence engenders violence--with ominous contemporary applications which Burrows doesn't hesitate to spell out.