Know why Beverly Hills was founded? So that a group of oil tycoons could live free of both nonwhites and the Hollywood nouveau riche. That's just one of the juicy cocktail-party anecdotes that fill Unreal Estate (Crown, $28), a social history of Los Angeles' super-wealthy told through profiles of 16 of its most lavish estates. Journalist Michael Gross (known for such dirt-dishing tomes as Model, Rogues' Gallery, and 740 Park) tells tales of adultery, prostitution, embezzlement, Mafia schemes, and the dauntless efforts of millionaires to keep the riffraff out of the exclusive enclaves of Beverly Hills, Bel Air, Holmby Hills, and Beverly Park. Example: Why did Sly Stallone pay $16 million for the property next door to his Beverly Park estate? To (allegedly) stop Suge Knight from moving in. Out now.