If you read biographies of artists to understand the people behind the work you love, you're always disappointed, because the facts never penetrate the mysteries. As Robert Gordon confesses near the end of his forthcoming biography of Muddy Waters, "Can't Be Satisfied," the "only way most anyone could get to know" Muddy Waters was through his music. And you don't need to read "Tonight at Noon," Sue Graham Mingus's eloquent memoir of her late husband, Charles, to know that he was volatile, bullying, childish, passionate, considerate, cruel and shrewd, and all before breakfast. You know that just listening to his music. But you read the biographies of artists for the stories and the dish--like the one about Mingus as a young man, riding his motorcycle through Los Angeles suburbs, where every time he spotted a black lawn jockey, he'd haul out the lariat he carried for just such occasions, rope the statue and decapitate it. In Gordon's biography of the father of urban, electrified blues, people captivate you simply by speaking. Band member James Cotton, describing Muddy's Mississippi homeplace, captures the poverty of Muddy's origins when he says, "There wasn't no entertainment but a big ole persimmon tree in the front yard." The mysteries of art pale beside people who can talk like this.