M

Fritz Lang's M arrived in 1931, his first sound film and one of the earliest German talkies. The film was based loosely on the contemporary Düsseldorf serial murders by Peter Kürten, then awaiting execution; Lang denied the connection, but the public made it anyway. The Nazi Party would denounce M within two years; Lang fled Germany in 1933.

A child murderer is terrorising Berlin. The police, applying mass surveillance and door-to-door checks, succeed mainly in disrupting the city's organised criminal economy. The criminal syndicates (pickpockets, beggars, fences) organise their own manhunt to find the killer and stop the police pressure. Peter Lorre, then twenty-six, plays Hans Beckert in a performance of haunted compulsion that defined his career and influences everything from Anthony Perkins's Norman Bates to Joaquin Phoenix's Joker.

Lang and his collaborator Fritz Arno Wagner pioneered techniques that would become foundational for sound cinema: the use of off-screen audio (the murderer is identified by his whistled fragment of In the Hall of the Mountain King), the kangaroo-court climax in which the criminal underworld stages its own trial, the way Lang refuses to show the violence but accumulates dread through space and silence. The film sits permanently in the upper tier of the Sight & Sound poll.

Why it's an Editor's Pick: The first great sound film, the first great serial-killer film, and the most influential single work of Weimar German cinema. Almost a century later, no procedural has surpassed its formal intelligence.