"IN 1967 YOUNG Tom Stoppard had his breakthrough hit, Rosencrantz and Guildenstern Are Dead, a brilliant play about actors playing characters playing actors playing characters, and the amusing, confusing jumble of fiction and reality. Stoppard knew he was onto something new and important. "I have a feeling," he said at the time, "that almost everybody today is more trying to match himself up with an external image he has of himself, almost as if he's seen himself on a screen."