IN 1965 BUSTER Keaton made a surprise appearance at the Venice Film Festival, where Film, a short movie he had made with Samuel Beckett, was being screened. The audience gave him a five-minute standing ovation. 'Sure, it's great,' he quipped, 'but it's all thirty years too late.'

Edward McPherson aims his new biography of Keaton at those who are just discovering him, a generation whose grandparents were born long after the heyday of the silent cinema. Modern viewers, armed with the DVD pause-bunon, can study the mechanics of films in a way that even film historians would