His memoir—Behind the Wheel of a War Ambulance by Robert Imbrie, New York: Robert M. McBride & Co.,1918.In late 1915 Imbrie enrolled as a volunteer driver in the American Ambulance Field Service, which was part of the Automobile Section of the French Army. He served in France from December 1915 until October, 1916, when he transferred to the Army of the Orient in Macedonia. He served there until April 1917, when the United States entered the war.