NATURAL BLONDE

Despite her claim that ''a memoir is an exercise in vulgarity, candor, excess and overkill,'' those traits are in short supply in this autobiography by the grande dame of dish, whose gentle pen has made her perhaps the only gossip writer who's actually liked by the celebs populating her syndicated daily column. Though the tabloids have made much of Blonde, claiming that Smith comes out in it, the Texas-born tattler does no such thing. She admits to a brief college lesbian affair but otherwise remains vague about her private life. That aside, she shares plenty of good-humored anecdotes about the likes of Joan Crawford, Tallulah Bankhead, Rock Hudson, and Truman Capote, and displays a wise ambivalence about her friendship with Roy Cohn. But in the end, it's less a memoir than a spun-out column. B-