When the Second World War began, Canada had no foreign intelligence capacity. Its political leaders had concluded that a clandestine service was not necessary to meet the nation's intelligence requirements. Yet Kurt F. Jensen argues that the country was a more active intelligence partner in the wartime alliance than has previously been suggested. Drawing on newly released materials and exhaustive research, 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 and established operations such as SIGINT, or Signal Intelligence, which intercepted and decrypted Vichy and Free French diplomatic communications. Cautious Beginnings spans the period from 1939 to 1951, when key policy and personnel structures were put in place. In the postwar years, Canada reconfigured its foreign intelligence operations to meet the challenges of a changing world, and by the early 1950s possessed resources that rivalled or exceeded those of many other nations. 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. Drawing on newly released materials and exhaustive research, this book will greatly interest students and academics in Canadian history, political science, military history, specialists in the field, and anyone interested in the often mysterious world of foreign intelligence.