Biography in: John Wakeman, editor. "World Film Directors, Volume One, 1890-1945". Pages 913-917. New York: The H.W. Wilson Company, 1987.
Directed four actors to Oscar nominations: Bette Davis (Best Actress, Now, Voyager (1942)), Gladys Cooper (Best Supporting Actress, Now, Voyager (1942)), John Dall (Best Supporting Actor, The Corn Is Green (1945)), and Joan Lorring (Best Supporting Actress, The Corn Is Green (1945)).
Rapper called casting Robert Alda in Rhapsody in Blue (1945) his biggest mistake. In retrospect he thought it should have been John Garfield.
His favorite of his films is The Brave One (1956).