General H.D.G. 'Harry' Crerar (1888-1965) was involved in or directly responsible for many of the defining moments of Canadian military history in the twentieth century. In the First World War, Crerar was nearly killed at the second battle of Ypres, was a gunner who helped to secure victory at Vimy Ridge, and was a senior staff officer during the pivotal battles of the last Hundred Days. During the Second World War, he occupied and often defined the Canadian army's senior staff and operational appointments, including his tenure as commander of First Canadian Army through the northwest European campaign. Despite his pivotal role in shaping the Canadian army, however, General Crerar has been long overlooked as a subject of biography. In A Thoroughly Canadian General, Paul Douglas Dickson examines the man and his controversial place in Canadian military history, arguing that Crerar was a nationalist who saw the army as an instrument to promote Canadian identity and civic responsibility. From his days as a student at the Royal Military College in Kingston, to his role as primary architect of First Canadian Army, the career of General H.D.G. Crerar is thoroughly examined with a view to considering and reinforcing his place in the history of Canada and its armed forces.