This subseries consists almost entirely of typescript copies of letters that Hamilton F. Corbett wrote to his family while serving in World War I. In addition to his time on the Western Front and recuperating from wounds, these letters cover Corbett's time as an aide-de-camp during the U.S. occupation of western Germany after the war, and include enclosed postcards of Luxembourg. Other materials are an original letter that Corbett wrote to his brother Henry L. Corbett; typescripts of letters to Corbett from Major General James A. Harbord; a certificate for his commission as an officer; typescript copies of letters written by Douglas McArthur and Charles T. Menonor; a newspaper clipping quoting one of Corbett's letters; and clippings of images related to the war, with handwritten contextual notes by Corbett.