Steven Spielberg likes to tell a story that captures the tension between art and commerce in 1970s Hollywood: In January 1973, the young filmmaker George Lucas screened a preview of American Graffiti , his movie about hot rods and ’60s kids. Among the hundreds of raucous fans filling San Francisco’s Northpoint Theatre was the Universal Pictures executive Ned Tanen, who was there to review changes requested by the studio. The audience loved what they saw, but Tanen hated it. “This film is a