Alberto Cavalcanti, Richard Massingham, Norman McLaren
Alberto Cavalcanti (1897–1982), Richard Massingham (1898–1953), and Norman McLaren (1914–1987) were directors associated at various points with the British GPO Film Unit and the broader Documentary Film Movement of the 1930s and 40s. Cavalcanti was a Brazilian-born director who worked in French avant-garde and then British documentary cinema and later returned to feature filmmaking in Britain and Brazil. Massingham was a British director who specialized in short instructional films for the General Post Office. McLaren was a Scottish-Canadian animator, one of the most important experimental animators in the history of cinema.