Wallis' papers are grouped into three series: general scrapbooks, military scrapbooks, and military diaries. General scrapbooks, covering the years 1908-1977, contain letters, photographs, and printed materials relative to Wallis' career. Some volumes include his diary for the period, and all are heavily annotated. They cover all aspects of his career from high school to post-retirement, with special emphasis on his military career and social life. Military scrapbooks contain the same variety of materials for the period 1911-1969, but are devoted exclusively to Wallis' activities during the two World Wars, and his roles in the Black Watch and as an Honorary A.D.C. Military journals give brief reports of his daily activities form 1941 to 1945.

Letters and diaries, including typescript transcriptions with photographs, newspaper clippings and ephemera.