Best known for his documentaries such as Drifters, North Sea, and Housing Problems, John Grierson was regarded as one of the most important figures in the British documentary film movement and one of the most influential of British film theorists. Grierson's conception of film as an instrument of social persuasion was derived from an aesthetic tradition based on philosophical idealism, and his theory of documentary film indicates that aesthetics and social purpose should have equal status. Ian Aitken explains the synthesis of naturalism and modernism which characterizes the idealistic strain of Grierson's social commentary and compares it to such contemporary social reformists as the Next Five Years Group and the Mass Observation researchers. He also draws out aesthetic and intellectual similarities between Grierson, Orwell and Priestley. By underlining the link between film and reform, he clarifies the meaning and significance of Grierson's ideas and the historical role of the documentary film movement. This book should be of interest to students and teachers of film studies and media studies.