Ray Westlake has an established reputation as a military historian specializing in the British army of the late nineteenth and early twentieth centuries. He has made a particular study of the Great War. He has published many articles and books, among them. Tracing British Battalions on the Somme, British Battalions on the Western Front January to June 1915, Voluntary Infantry, 1880-1908, Kitchener's Army, British Regiments at Gallipoli, British Battalions in France and Belgium 1914, English and Welsh Regiments, The Territorial Battalions, The British Army of August 1914: An Illustrated Directory and Tracing the Rifle Volunteers.