The author prefaces his consideration of films as an art form with a discussion of the mechanics of filmmaking. He describes the division of talent on a movie set, details the history of the tools of filmmakers, and explains the production and reproduction of a film. The influence of film techniques on plot development in a fiction film is illustrated with scenes from famous motion pictures. A psychological explanation is offered for building up a scene from selected fragments of action. This technique of editing is described, using films by D. W. Griffiths and Sergei Eisenstein as classic examples. The effect of a "natural" sound tract is differentiated from that of a "non-natural" one. A description of the filming process includes an explanation of the problems involved in camera set-up, lighting, and choosing lenses. Film music, the author suggests, not only establishes the mood of a film, but actually contributes to the development of the plot. Two requirements of good film criticism are proposed: a consciousness of the effect produced by a film and the ability to discuss the effect intelligently. Famous film critics are quoted on the subject of films as a medium for entertainment and instruction. In conclusion, the author urges that films are a form of art more akin to poetry than to prose. A glossary lists film terms as they are commonly used in Great Britain. (JY)