This rousing mythbuster about New York's post-Civil War Democratic ""Boss"" Tweed comes from the author's journey through the municipal archives, allegedly untouched by prior researchers. He charges that Tweed's ferocious bossism and graft are essentially a fabrication originated by hostile 19th-century newspapers and perpetuated with no review of the evidence. The myth: Tweed, an Irish or perhaps Jewish king of the Tammany machine, appropriated staggering amounts of public funds for himself and his ""Ring"" of cronies until brought to justice in 1873. Hershkowitz' findings: Tweed, a Protestant of Scots descent, a local fire commissioner and Odd Fellow lodgeman, entered politics during the lower-middle-class upsurge of the 1850s, and held a series of state and city offices in rather mediocre, passive fashion, initiating public-service improvements while warming a nest-egg as a corporate director. No graft was proven, however. After years of Republican scandal-mongering, he was sentenced for the technical crime of failure to audit--then spent 12 additional years in prison without a trial, subject to $3 million bail. No member of the ""Ring"" came to his defense--because, according to Hershkowitz, the omnipotent ""Ring"" never existed. Nor did the Tammany menace, a mere component in the ""fractured"" flux of New York politics magnified by the Republican-paid cartoonist Thomas Nast. The book concludes that Tweed was ""simply a big target. . . useful as an electoral gimmick, and Republicans were desperate"" after the Grant Administration's corruption. ""Most importantly, by now  Tweed was identified as the leading spokesman for the interests of the city and the immigrant."" Hershkowitz' challenging, sharply rendered particulars are sure to be challenged in turn; the book has already had front page New York Times attention.