The emerging threat of a militarily powerful Soviet Union after the Second World War caused the United States to rearm and look to the defence of its northern approaches against a possible Soviet bomber attack. The Canadian government, although less apprehensive about this military threat than the American, realized the necessity of accommodating its neighbour's urgent desire for security and ought to avoid a US-Canada bilateral pact by a multilateral defence treaty and organization linking the democracies of Western Europe and North America. The fourth volume of James Earys' highly acclaimed history of Canadian defence and external affairs studies the government's role in forming the North Atlantic Treaty Organization; its attempts, partly successful, to give the alliance the functions and authority it considered suited to Canadian interests and those of the Western democracies; and the problems it tried to deal with as a member of the Alliance - problems mobilizing the deterrent, of sharing the burden, and of explanding membership to include Greece, Turkey, and Western Germany. These decisions, made some thirty years ago, have shaped the course of Canadian foreign policy ever since, and continue to have ramifications for Canadian life today.