The great documentarist Robert Flaherty (Nanook of the North, Moana) created this study of life in the Depression dust bowl for the U.S. Department of Agriculture, which promptly repressed it. Flaherty wanders far afield from the social programs that were his assigned subject, concentrating on the suffering of migrant workers and the apparent hopelessness of their position. Moving, even majestic, it remains a remarkable film, if not one of Flaherty’s best.