316 pp. Mario Puzo spent the last three years of his life writing Omerta, the concluding installment in his saga about power and morality in America. In The Godfather, he introduced us to the Corleones. In The Last Don, he told the wicked tale of the Clericuzios. In Omerta, Puzo chronicles the affairs of the Apriles, a family on the brink of legitimacy in a world of criminals.