Son of Olga Emily Boissevain and Bram van Stockum. Younger brother of Hilda van Stockum Marlin. Trinity College, Dublin. Ph.D., University of Edinburgh. Institute for Advanced Study, Princeton, spring 1939. Taught at Univ of Maryland until WWII. Time Travel Pioneer. Pilot of RAF Halifax bomber, shot down over Laval, France, on his sixth mission, D-Day fortnight, June 10, 1944.