Papers relating to his military career, 1939-1962, principally his service in Burma, 1939-1941, UK, 1941-1943, North Africa, 1943, Italy, 1943-1944, and Korea, 1955-1956, notably including battalion orders for 2 Bn, Sherwood Foresters, 1945; German propaganda leaflets for US and Allied troops, [1944]. 'An ancient Yorkshire family', a history of the Slingsby family, written by Slingsby in 1989.

Anti-British propaganda leaflet, in Arabic, Hindi, and Urdu; anti-British propaganda leaflet calling for the Indian Independence League in East Asia to assist the Japanese in ridding Asia of all British influences; anti-French propaganda leaflet distributed in Indo- China announcing the fall of Singapore to the Japanese, 1942