At the height of the war in 1943, the future head of the First Canadian Army, General Harry Crerar, penned a long memorandum in which he noted that there was still much confusion as to "what constitutes an 'Officer.'" His words reflected the army's preoccupation with creating an ideal officer who would not only satisfy the immediate demands of war but also conform to pervasive, little-discussed notions of social class and masculinity. Drawing on a wide range of sources and exploring the issue of leadership through new lenses, this book looks at how the army selected and trained its junior officers after 1939 to embody the new ideal. It finds that these young men - through the mentors they copied, the correspondence they left, even the songs they sang - practised a "temperate heroism" that distinguished them from the idealized, heroic visions of officership from the First World War, and also from British and even German representations of wartime officership. Fascinating and highly original, Crerar's Lieutenants sheds new light on the challenges many junior officers faced during the Second World War - not only on the battlefield but from Canadians' often conflicted views about social class and gender.