A lost film is a feature film or short film that is no longer known to exist in studio archives, private collections or public archives such as the Library of Congress, where at least one copy of all American films are deposited and catalogued for copyright reasons. Of American silent films far more have been lost than have survived, and of American sound films made from 1927 to 1950, perhaps half have been lost. The phrase "lost film" can also be used in a literal sense for instances where footage of deleted scenes, unedited and alternative versions of feature films are known to have been created but can no longer be accounted for. Sometimes a copy of a lost film is rediscovered. A film that has not been recovered in its entirety is called a partially lost film. For example, the 1922 film Sherlock Holmes was eventually discovered but some of the footage is still missing. Quite often a lost film of a major (i.e. Hollywood) production studio may have still photographs, shot at the time of production, often on glass negative. Glass negatives, if properly maintained, can last indefinitely, preserving image fidelity.

Lost may refer to:

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects. The process of filmmaking has developed into an art form and industry.

Films are cultural artifacts created by specific cultures, which reflect those cultures, and, in turn, affect them. Film is considered to be an important art form, a source of popular entertainment and a powerful method for educating – or indoctrinating – citizens. The visual elements of cinema give motion pictures a universal power of communication. Some films have become popular worldwide attractions by using dubbing or subtitles that translate the dialogue into the language of the viewer.

Films are made up of a series of individual images called frames. When these images are shown rapidly in succession, a viewer has the illusion that motion is occurring. The viewer cannot see the flickering between frames due to an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Viewers perceive motion due to a psychological effect called beta movement.

Dian Fossey (/daɪˈæn ˈfɒsi/; January 16, 1932 – December 27, 1985) was an American zoologist who undertook an extensive study of gorilla groups over a period of 18 years. She studied them daily in the mountain forests of Rwanda, initially encouraged to work there by famous anthropologist Louis Leakey. She was murdered in 1985; the case remains open.

Called one of the foremost primatologists in the world while she was alive, Fossey, along with Jane Goodall and Birutė Galdikas, was part of the so-called Leakey's Angels, a group of three prominent researchers on primates (Fossey on gorillas; Goodall on chimpanzees; and Galdikas on orangutans) sent by archaeologist Louis Leakey to study great apes in their natural environments.

When her photograph, taken by Bob Campbell, appeared on the cover of National Geographic Magazine in January 1970, Fossey became an international celebrity, bringing massive publicity to her cause of saving the mountain gorilla from extinction, as well as convincing the general public that gorillas are not as fierce as they are sometimes depicted in movies and books. Photographs showing the gorilla "Peanuts" touching Fossey's hand depicted the first recorded peaceful contact between a human being and a wild gorilla. Her extraordinary rapport with animals and her background as an occupational therapist brushed away the Hollywood "King Kong" myth of an aggressive, savage beast. Fossey made discoveries about gorillas including how females transfer from group to group over the decades, gorilla vocalization, hierarchies and social relationships among groups, rare infanticide, gorilla diet, and how gorillas recycle nutrients. Fossey's research was funded by the Wilkie Foundation and the Leakey Home, with primary funding from the National Geographic Society.

Charles Robert Redford, Jr. (born August 18, 1936), better known as Robert Redford, is an American actor, film director, producer, businessman, environmentalist, philanthropist, and founder of the Sundance Film Festival. He has received two Oscars: one in 1981 for directing Ordinary People, and one for Lifetime Achievement in 2002. In 2010 he was awarded French Knighthood in the Legion d'Honneur. At the height of his fame in the 1970s and 1980s, he was often described as one of the world's most attractive men and remains one of the most popular movie stars. His popular films include Butch Cassidy and the Sundance Kid (1969), Downhill Racer (1969), Jeremiah Johnson (1972), The Candidate (1972), The Sting (1973), The Way We Were (1973), The Great Gatsby (1974), Three Days of the Condor (1975), The Great Waldo Pepper (1975), All the President's Men (1976), A Bridge Too Far (1977), The Natural (1984), Out of Africa (1985), Sneakers (1992), Indecent Proposal (1993),The Last Castle and Spy Game (2001). As a filmmaker, his notable films include Ordinary People (1980), The Milagro Beanfield War (1988), A River Runs Through It (1992), Quiz Show (1994), The Horse Whisperer (1998) and The Legend of Bagger Vance (2000).