The Boy in Blue (German: Der Knabe in Blau and also known as Emerald of Death) is a 1919 silent German drama film directed by F. W. Murnau. It was Murnau's directorial debut. The film is now considered to be a lost film, though the Deutsche Kinemathek film archive possesses 35 small fragments ranging from two to eleven frames in length. Thomas Gainsborough's painting The Blue Boy and Oscar Wilde's novel The Picture of Dorian Gray were inspirations for Murnau to create this film.