The offices of Robert Greenwald Productions occupy a slightly rundown, horseshoe-shaped building in Los Angeles, just down the street from Culver Studios, the legendary movie facility where ''Gone With the Wind'' and ''Citizen Kane'' were filmed. Back in the day, the R.G.P. building, then a motel, was used by studio executives for liaisons with starlets and mistresses. Though no longer a Hollywood love nest, it still has a whiff of the illicit about it -- and still operates in the shadow of several corporate studios.

Robert Greenwald, a 58-year-old film producer and director with a number of commercially respectable B-list movies under his belt, has always tried to imbue his work with a left-leaning political sensibility. R.G.P. has been involved in the making of some 50 movies, including ''Steal This Movie,'' a 2000 film based on the life of the radical activist (and Greenwald's friend) Abbie Hoffman, and ''Crooked E,'' a satirical TV movie about Enron's collapse that CBS broadcast last year. Greenwald is presumably the only director in Hollywood to adorn his workspace with a quotation from Walt Whitman's ''Leaves of Grass'': ''The attitude of great poets is to cheer up slaves and horrify despots.''

One morning in late May, I visited Greenwald at his studio to watch the making of his latest documentary, ''Outfoxed: Rupert Murdoch's War on Journalism,'' which will have its premiere this Tuesday at the New School University in New York. Over the past couple of years, Greenwald has developed a ''guerrilla'' method of documentary filmmaking, creating timely political films on short schedules and small budgets and then promoting and selling them on DVD through partnerships with grass-roots political organizations like MoveOn.org. The process, in addition to being swift, allows him to avoid the problems of risk-averse studios and finicky distributors. His 2003 film ''Uncovered: The Whole Truth About the Iraq War,'' a documentary that was critical of the Bush admi...