"The Testament of Dr. Mabuse" is a 1933 German film directed by Fritz Lang. It serves as a sequel to the earlier film, "Dr. Mabuse, the Gambler." The story revolves around the criminal mastermind Dr. Mabuse, who, despite being in a mental institution, continues to exert influence over the criminal underworld through his writings. The film combines elements of crime, horror, and psychological thriller, showcasing Mabuse's ability to manipulate others. It reflects the socio-political climate of the time, particularly the rise of Nazism in Germany. The film is notable for its innovative use of sound and visual storytelling techniques.