Kurt F. Jensen argues that Canada was a more active intelligence partner in the Second World War alliance than has previously been suggested. He describes Canada’s contributions to Allied intelligence before the war began, as well as the distinctly Canadian activities that started from that point. He reveals how the government created an intelligence organization during the war to aid Allied resources. This is a convincing portrait of a nation with an active role in Second World War intelligence gathering, one that continues to influence the architecture of its current capabilities.