Carl Mayer was an Austrian screenwriter. Mayer wrote or co-wrote the screenplays to The Cabinet of Dr. Caligari (1920), The Haunted Castle (1921), Der Letzte Mann (1924), Tartuffe (1926), Sunrise: A Song of Two Humans (1927), and 4 Devils (1928), most of them being films directed by F. W. Murnau. Mayer was a fundamental figure in the dramatic and narrative establishment of both German expressionist cinema and Kammerspielfilm.