During the location shooting of The Madness of King George, one fellow looked out of place. Or thought he did. "We're in this country house," Alan Bennett recalls, "with all the vans and caravans and the whole invading army of mercenaries. And I felt that everyone had something purposeful to do there-except me." No matter that director Nicholas Hytner and the crew were, like expert midwives, carefully bringing Bennett's 1991 play to the screen; the creator was still adrift. "I'd started it all by telling the story," he says, "but I felt as if I didn't have a function anymore."
The...