Compelling, extraordinarily resonant account of the last days of a failing Mafia don, written by the two FBI agents who managed to infiltrate Paul Castellano's Staten Island estate and gather evidence that eventually led to the indictment of many major Mafia kingpins in the highly publicized mob-busting Commission case of 1985. In telling the story of the increasingly reclusive Castellano, O'Brien and Kurins probe into the byzantine background of today's Mafia, pointing out, for example, that the 1957 Appalachian meeting of mob figures from across the country marked ``the dividing line between the `old' Mafia of Al Capone and Salvatore Maranzano and the `new' Mafia that would eventually be headed by Paul Castellano.'' The authors are equally effective when discussing such matters as the PR-ing of the mob, the linkage between such films as The Godfather and the wise-guy attitudes of many Mafia members, and the use of ``heart trouble'' as a Mafia dodge when facing prosecution. It is in documenting the intimate, behind-the- scenes details of Paul Castellano's life, however, that O'Brien and Kurins excel. Having successfully planted a listening device in the capo's home, they learn of his affair with his maid, of his impotence, and of the pressures being put on him by rival mobsters. In the process, the agents come to feel a grudging sympathy for the proud, beleaguered old man. When Castellano is eventually indicted and then gunned-down on a midtown Manhattan street, the authors admit to being saddened. An exciting and yet unexpectedly moving human document, done with occasional street-smart humor and lots of style.