Even if you're the sort of person who decorates your foyer with vintage posters of ''Mean Streets'' and ''Bring Me the Head of Alfredo Garcia,'' has read Peter Biskind's ''Easy Riders, Raging Bulls'' three times, and is convinced that no one could tell you anything you don't know about the American film renaissance of the 1970s, it's still an intoxicating pleasure to experience the savvy, detailed, altogether yeasty piece of nostalgia that is A Decade Under the Influence. Directed by Richard LaGravenese and the late Ted Demme (his final film), this documentary about the triumph of the New Hollywood employs a treasure trove of interviews and clips to create a rich understanding of the many forces -- cultural undertows, really -- that flowed together to fill the void left by the dying studio system.
The burst of influences looked, at the time, almost random: Cassavetes, the new wave, Roger Corman. Yet as director Sydney Pollack points out, what had ultimately changed was the audience. The revolution of ''Easy Rider,'' ''M*A*S*H,'' ''Midnight Cowboy,'' and dozens of other works of popular art was that people now embraced the notion that movies could transcend the fanciful and exotic to mirror life as it was. The title ''A Decade Under the Influence'' raises a question: Under the influence of what? The film's answer: a belief that entertainment and reality needn't be mortal enemies.