Papers relating to his life and career, 1917-1963, principally comprising official correspondence with Lt Gen M Brocas Burrows, British Military Mission, Moscow, 1944-1945, Gen Mark Wayne Clark, US Army, 1943-1944, 1951-1952, Maj Gen Richard Henry Dewing, UK Army and RAF Liaison Staff, Australia, 1943-1944, Maj Gen Gordon Edward Grimsdale, Military Attaché andhead of Military Mission to Chungking, China, 1942-1943, AF Sir Roger John Brownlow Keyes, Bt, Director of Combined Operations, War Office, 1940-1942, Lt Gen Sir Henry Pownall, South East Asia Command HQ, 1944-1945, Lt Gen Sir Harold Redman, British Joint Staff Mission, Washington DC, 1943-1944, AF Sir James Somerville, Commander-in-Chief Eastern Fleet, 1943-1947, and Maj Gen Sir Edward Spears, Minister to the Lebanon, 1940-1944, and Lt Gen Albert C Wedemeyer, US Army, Deputy Chief of Staff; South East Asia Command, 1944; personal correspondence with and about FM Lord Alanbrooke, 1946-1947, 1957-1963, FM Sir Claude John Eyre Auchinleck, 1941-1961, and FM Archibald Percival Wavell, Viscount Wavell of Cyrenaica and of Winchester, 1943-1946; official andpersonal correspondence with Dwight David Eisenhower, 1942-1965, and AF Louis (Francis Albert Victor Nicholas) Mountbatten, 1st Earl Mountbatten of Burma, 1943-1954, 1960-1964; correspondence with publishers and colleagues, including Gen Sir Richard Nugent O'Connor; papers relating to India, 1947-1951, including his correspondence as Chief of Staff to Mountbatten, 1947, notes on interviews with Jawaharlal Nehru and Mahomed Ali Jinnah, 1947, letters describing the political situation in India, 1947-1948, and correspondence concerning compensation for Indian Government servants, 1948-1951; correspondence concerning the proposed defence reorganisation, 1955-1963; papers relating to his service as Secretary General, NATO (North Atlantic Treaty Organization), 1952-1957, including his official progress reports, 1952-1956; newspaper cuttings, statements to the press and texts of speeches and broadcasts, 1952-1957; papers relating to his memoirs, [1940-1960] including correspondence with publishers, 1960-1961, and colleagues, 1957-1960, notebooks, 1940-1960, and drafts and proofs, [1960]. newspaper cuttings, 1943, 1948, 1951-1952, 1957; texts of speeches, 1943-1958; correspondence relating to operations in Somaliland, 1917-1920; notes and papers relating to his studies at Staff College, Quetta and RAF Staff College, 1922-1924. Papers relating to Rt Hon Sir Winston (Leonard Spencer) Churchill, 1940-1965, including personal correspondence with Churchill, 1940, 1943-1945, 1947-1964; correspondence relating to Churchill's memoir The Second World War (Cassell, London, 1948-1954), 1946-1956, including correspondence relating to Dieppe Raid, Aug 1942, dated 1950, and galley proofs, [1948-1954]. Printed material, 1941-1945, 1947, 1951, notably including copies of telegrams sent by Winston Churchill as Prime Minister, 1941-1942; minutes of Chiefs of Staff meetings, 1943-1944; minutes of Combined Chiefs of Staff meetings, 1943, 1945.

The collection consists of pamphlets written by Davidson, papers relating to his part in the Allied Military Mission to Moscow, USSR, 1939 and papers relating to his career in World War Two as Commander in the Royal Artillery and as Director of Military Intelligence. The World War Two material includes maps used in the retreat of the BEF (British Expeditionary Force) to Dunkirk, France, maps used as Director of Military Intelligence to illustrate the progress of the war to Queen Mary, mother of George VI and a personal diary kept while Director of Military Intelligence. There is also a file containing correspondence with E E Thomas of the Cabinet Office Historical Section relating to aspects of Military Intelligence during World War Two.

Correspondence relating to Collier's work as Air Attaché in Moscow, 1934-1937, and as Head of the Air Section of the British Military Mission to Moscow, 1941, with particular reference to the role of Brig Gen Philip R Faymonville, United States Army, Military Attaché and later Lend-Lease Administrator in Moscow, 1934-1943, in relations between the USA and the USSR during the period 1918-1943, consisting of photocopies of letters to Collier from Lt Col Thomas A Julian, Associate Professor of History at the USAF Academy and carbon copies of Collier's replies, dated 1968-1969.