Playboy says its founder, Hugh Hefner, has died of natural causes at the age of 91. The pipe-smoking hedonist revved up the sexual revolution in the 1950s and went on to build a multimedia empire of clubs, mansions, movies and T-V. Asked by The New York Times in 1992 what he was most proud of, Hefner responded — quote — “That I changed attitudes toward sex.” At its peak, Playboy had more than seven-million readers, although its circulation has declined in recent years.