Ernest Hemingway's enlistment with the American Red Cross during World War I was one of the most formative experiences of his life, and it provided much of the source material for A Farewell to Arms and his writings about Italy and the Great War. As significant as it was, Hemingway's service has never been sufficiently understood. By looking at previously unexamined documents, including the letters and diary of Hemingway's commanding officer, Robert W. Bates, official reports of the ambulance and canteen services, and...