A number of Alfred Hitchcock's films have been remade, with official remakes of Murder! and The Man Who Knew Too Much being directed by Hitchcock himself. North by Northwest and Saboteur are also considered by some scholars to be unofficial remakes of Hitchcock's English espionage thriller The 39 Steps.[1][2][3] This list does not include sequels (such as the films that followed the 1960 version of Psycho).