The most important and internationally influential development in British cinema was the documentary film movement led by John Grierson in the 1930s and 1940s. This is a political and social history of that movement, which was characterized by actuality-based films made outside the commercial industry. Based on examinations of official government records, the study provides a fascinating picture of the relationship forged between Grierson and the civil service bureaucracy for his own needs and the needs of his country. The book offers a fresh look at a rare moment in the history of cinema when a different mode of production, philosophy, and source of funding permitted a determined group to create a distinguished body of work.