The collection documents Garlock's military career. The main portion of the collection consists of correspondence between Garlock and his family while he was on active duty. Early Spanish-American War (1898) letters from Garlock originated at Camp Harvey, Wisconsin, and Camp Cuba Libre, Florida. A few letters (1916) were written by Garlock from Camp Wilson, San Antonio, Texas, when the raids of Pancho Villa prompted the U.S. Army to activate several National Guard units.
The most significant correspondence was written by Lt. Colonel Garlock to his wife Anna and children while he was serving in World War I. Included are letters from training camps in Waco, Texas, and Fort Sill, Oklahoma; as well as from overseas. They present detailed accounts of Army training activities, effects of the war on the French countryside, conditions in the trenches and the daily routine of American officers in France and in Germany with the occupation army. Correspondence is filed chronologically. His active duty is also described briefly by three diaries which he kept in 1898, 1917, and 1918.
One folder of miscellaneous papers including post war correspondence and photographs of his army service is filed at the end of the collection.
