It's one of my favorites, too, Mrrzy-Joel McCrea is the best, as is the cheerfully homicidal Edmund Gwenn. Herbert Marshall is the seemingly noble but secretly evil father figure, which is a recurring Hitchcock theme. Just looked it up and found that it had an unusually large number of (famous) writers including Robert Benchley, Charles Bennett, Harold Clurman, Joan Harrison, Ben Hecht, James Hilton, John Howard Lawson, John Lee Mahin, Richard Maibaum, and Budd Schulberg--maybe that's why it's so good...