Nanook of the North is a 1922 American silent film which combines elements of documentary and docudrama/docufiction, at a time when the concept of separating films into documentary and drama did not yet exist. In the tradition of what would later be called salvage ethnography, the film follows the struggles of the Inuk man named Nanook and his family in the Canadian Arctic. It is written and directed by Robert J. Flaherty, who also served as cinematographer, editor, and producer. Some have criticized Flaherty for staging several sequences, but the film has been described by Roger Ebert as "stand[ing] alone" among Flaherty's films "in its stark regard for the courage and ingenuity of its heroes." It was the first feature-length documentary to achieve commercial success, proving the financial viability of the genre and inspiring many films to come. In 1989, Nanook of the North was among the first group of 25 films selected by the Library of Congress for preservation in the United States National Film Registry for being "culturally, historically, or aesthetically significant". The documentary follows the lives of an Inuk, Nanook, and his family as they travel, search for food, and trade in the Ungava Peninsula of northern Quebec, Canada. Nanook, his wife Nyla and their family are introduced as fearless heroes who endure rigors no other race could survive. The audience sees Nanook, often with his family, hunt a walrus, build an igloo, go about his day, and perform other tasks. In 1910, Flaherty was hired by Sir William Mackenzie as an explorer and prospector searching for iron ore and other mineral deposits along the Hudson Bay for the Canadian Northern Railway. Learning about the lands and people there, Flaherty decided on his third expedition in 1913 to bring with him a glass-plate still camera and movie camera as well as a small portable printer and processor. Knowing nothing about film, he took a three-week course on the elementary techniques of filmmaking and film processing with the Eastman Kodak Company in Rochester, New York.