<p>When he was promoted to officer rank at eighteen, S. L. A. MARSHALL was the youngest shavetail in the United States Army during World War I. He rejoined the Army in 1942, became a combat historian with the rank of colonel; and the notes he made at the time of the Normandy landing are the source of this heroic reminder. Readers will remember his frank and ennobling book about Korea, THE RIVER AND THE GAUNTLET, which was the result of still a third tour of duty.</p>