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.

Papers relating to his service in the Far East in 1942-1945 and 1950, dated 1942-1945 and 1950, principally comprising two photograph albums of Keijo (Seoul) POW camp, 1942-1944; copy of obituary from The Lancashire Lad, North Lancashire Regt (Loyal Regt) journal (Dec 1950); copy of covering letter to the Centre from Joan Procter (Procter's sister), 1992.

French revolutionary pamphlets collection comprises pamphlets by the Interior Ministry, the Police Ministry and other official bodies in the French republic. Pamphlet by the Chief of Police Sotin warns citizens that the enemies of the revolution are regrouping (c1794). A pamphlet of 1795 also urges vigilance.