"Gilroy was writing the screenplay for The Devil's Advocate, the Keanu Reeves legal horror film that postulated Al Pacino as Satan -- Mephistopheles on a retainer -- and he toured law firms in New York to do research.
"I was sort of wandering on a tour and was just struck at just how huge this backstage area is," Gilroy recalled recently at the Toronto film festival, where Michael Clayton was screened. "It's sort of like a restaurant: no one ever goes in the kitchen. I thought someone should do a movie back here. There's got to be a movie. There's got to be 20 movies back here."