Papers and photographs, 1888-1924, 1972, mostly manuscript letters by Simpson-Baikie to his wife, Marion Evelyn Simpson-Baikie, Lady Simpson-Baikie, 1906-1919, including letters whilst on active service on the Western Front, Gallipoli, Salonika and Palestine, 1914-1918; four manuscript letters from Simpson-Baikie to his mother-in-law, Emilita Miller, 1904-1918, and three manuscript letters from Simpson-Baikie to his daughter, Jean Simpson-Baikie, 1917-1918. Also, manuscript letter from Gen Sir Ian Standish Monteith Hamilton to Jean Miller Hamilton, Lady Hamilton, asking her to inform Marion Evelyn Simpson-Baikie that Simpson-Baikie has been chosen to serve at Gallipoli, 1915; manuscript letter to Simpson-Baikie from Gen Sir Horace Lockwood Smith-Dorrien, Governor of Gibraltar, on adverse comments about Smith-Dorrien in 1914 (Spiers, London, 1919) by FM John Denton Pinkstone French, 1st Viscount of Ypres, 1920. Eleven photographs and two negatives relating to Simpson-Baikie's career, 1888-1920, including three photographs of Simpson-Baikie, 1888, [1904]; Lt Gen Horatio Herbert Kitchener, 1st Baron Kitchener of Khartoum, General Officer Commanding in Chief, South Africa, with his Aide de Camp, Lt Francis Aylmer Maxwell [1901]; Maj Gen Hubert Ion Wetherall Hamilton, Maj Gen General Staff, Mediterranean Command, 1911; Gen Sir Ian Standish Monteith Hamilton at Charing Cross station, London, on his departure for Gallipoli, 13 Mar 1915; aerial photograph of the French camp at Sedd el Bahr, Gallipoli, Turkey, 1915. Typescript letter to Jean Morley Kennerley (née Simpson-Baikie) from Professor Robert Clifford Walton concerning Smith-Dorrien, 1972.

Narrative diaries, nine manuscript volumes, as Maj commanding motorised cavalry sqn, 4/7 Dragoon Guards, Palestine, 1938-1939, with typescript nominal roll of officers, non-commissioned officers and men who served with 4/7 Royal Dragoon Guards Sqn in Palestine, 1938-1939. Also, two albums of related captioned photographs and one map of Syria and Palestine, scale 1: 1,140, 000 [1935].