This diary details Samuel P. Fay's experience with the American Ambulance Field Service (later to be known as the American Field Service, abbreviated “AFS”) with Section Sanitaire [États-] Unis (SSU) 1 in Belgium relating to retrieving wounded from postes de secours, German artillery bombardments, the novelty of airplanes, the maintenance of the motor pool, and general impressions of the war, including movements of British, French, and Belgian troops as well as descriptions of trench design.  The diary includes mention of other ambulance drivers and staff, including AFS founder A. Piatt Andrew and fellow volunteer Joshua G.B. Campbell.