Genres are categories of kinds or types of artistic or cultural artifacts with certain elements in common. In film, common generic elements include subject matter, theme, narrative and stylistic conventions, character types, plots, and iconography. In film studies, the term serves simultaneously as: (1) An industrial approach, in which production, especially during the Hollywood studio era (1920s–1950s), is standardized, and marketing is geared toward concept labeling and packaging; (2) A consumer index, providing audiences with a sense of the kind of pleasures to be expected from a given film; and (3) A critical concept, a tool for theorizing relations between films and groups of films and for understanding the complex relationship between popular cinema and popular culture, and for mapping out a taxonomy of popular film.
Genres preceded cinema but were fundamental to it. The western, for example, was already established in literature before the invention of film, while the musical took much from preexisting theatrical forms. Classical literary theory distinguished differences between literature and popular writing and assumed judgments based on underlying assumptions of aesthetic value. Popular art, including film, is formulaic, and it has often been similarly criticized for lacking originality. However, genre theorist John Cawelti suggests that all art be thought of as existing on a continuum between invention and convention—a perspective that allows for a greater appreciation and understanding of genre texts and how they work.
Because genre movies are collaborative efforts that require the work of many individuals, they have been commonly understood as particularly good barometers of cultural attitudes, values, and trends. This is true not only of individual genre movies, but also of the changing patterns and popularity of different genres and of the shifting relationships between them. For whether they are set in the past or in the future, on the mean streets of contemporary New York City or long ago in a galaxy far away, genre movies always are about the time and place in which they are made.