in its use of "cross-cutting" in film editing to show simultaneous action in different places. No earlier film had created such swift movement or variety of scene. The Great Train Robbery was enormously popular. For several years it toured throughout the United States, and in 1905 it was the premier attraction at the first nickelodeon. Its success firmly established motion pictures as commercial entertainment in the United States. After The Great Train Robbery Porter continued to try out new techniques. He presented two parallel stories in The Kleptomaniac (1905), a film of social commentary like his technically more conventional film of 1904, The Ex-Convict. In The Seven Ages (1905) he used side lighting, close-ups, and changed shots within a scene, one of the earliest examples of a filmmaker departing from the theatrical analogy of a single shot for each scene. He also directed trick films such as Dream of a Rarebit Fiend (1906), based on the comic strip by Winsor McCay. Between 1903 and 1907 he successfully demonstrated most of the techniques that were to become the basic modes of visual communication through film. For instance, he helped to develop the modern concept of continuity editing, notably in The Trainer's Daughter or A Race for Love (1907), and is often credited with discovering that the basic unit of structure in film was the "shot" rather than the scene (the basic unit on the stage), paving the way for D. W. Griffith's advances in editing and screen storytelling. Yet he seemed to regard them only as separate experiments and never brought them together in a unified filmmaking style. Porter directed future filmmaker Griffith in Rescued from an Eagle's Nest (1908). Defender and Rex Film Companies In 1909 after tiring of the industrial system set up to feed the booming nickelodeon business, Porter left Edison and founded a company to manufacture Simplex motion picture projectors. In 1910 he founded Defender Film Company, which folded after one year. In 1911 he joined with others in organizing the Rex Motion Picture Company. In 1912 he sold out and accepted an offer from Adolph Zukor to become chief director of the new Famous Players Film Company, the first American company that regularly produced feature-length films. He directed stage actor James K. Hackett in their first feature film, The Prisoner of Zenda (1913). He also directed Mary Pickford in her first feature film, A Good Little