One of the great reformers in naval gunfire and employment of destroyer ships. Commander of U.S. Naval Forces in European waters during World War I, he adopted the use of naval convoys and promoted the construction of destroyers to counter Germany’s use of unrestricted submarine warfare. He served as President of the Naval War College in 1917 and from 1919 to 1922. His book on Anglo-American naval cooperation in the war at sea during World War I, Victory at Sea, won the Pulitzer Prize in history in 1920.