The son of a prominent Canadian politician, Hume Cronyn made his stage debut with the Montreal Repertory Theatre in 1930 while still a student at McGill University and reached Broadway in 1934, playing the Janitor in "Hipper's Holiday." Short and wiry, he gained a reputation for excellence onstage, adroitly portraying ordinary people, and would later prove his versatility by branching into directing, producing and playwriting. An early appearance on the new medium of TV (a 1939 NBC presentation of "Her Master's Voice") preceded Cronyn's first feature role as the literal-minded, snooping, armchair detective-neighbor in Alfred Hitchcock's understated thriller "Shadow of a Doubt" (1943). He also collaborated on the screenplays for Hitchcock's "Rope" (1948, with Arthur Laurents) and "Under Capricorn" (1949, with James Birdie), as well as playing the ship's radio operator in the director's "Lifeboat" (1944).