There has been no new material on Hoover's personal history since a 1937 New Yorker piece, Demaris says. This book consists of interviews with Hoover's subordinates, associates, relatives, friends and enemies. They describe his profuse small talk, his gallery of nude paintings and his Chinese Chippendale, his impartial ignorance of culture and science. No one is sure whether J. Edgar had an active homosexual relationship with Clyde Tolson, the man he lived with, but he certainly seems to have been a textbook anal sadist with his miserliness, fondness for mean practical jokes, collector's mania, and anti-Communist ferocity. He is also reported to have told a top Mafioso in the Stork Club that they had best respect each other's turfs. The hero of the book is William Sullivan, Hoover's number three man for years, who broke with The Boss over the latter's unwillingness to subordinate himself to the CIA-sponsored Law Enforcement Assistance Administration, which began sophisticated counterinsurgency in the 1960's. Sullivan calls Hoover a ""master con man,"" a tax cheat, a blackmailer, an anti-Semite and a racist, and says he was well aware of the Watergate plumbers' operation but wanted to stay clean of it himself. Demaris does not fail to report that Sullivan was the major booster of schemes to install dictatorship in the event of a ""national emergency""--the so-called Huston Plan--but presents Sullivan as a marvelously bluff and liberal old codger compared with the hydrocephalous Hoover. His descriptions of Hoover's bureaucratic style are a high point of the book, along with the checkerboard of reminiscences about the Truman, Nixon and Kennedy administrations. Demaris, a writer for Ramparts and author of The Green Felt Jungle, ends with the reminder that mudslinging has become indiscriminate these days and Hoover was, after all, unique. A sure best-seller.