The authors argue that despite a shared continent and heritage, ambivalence has always characterized relations between the two countries - an ambivalence stemming from differences that Americans underestimate and that Canadians overstate. Thompson and Randall begin with the century in which Canada was a pawn in the relations between the United States and Great Britain. They consider the years until World War II, during which Canada and the United States erected many of the bilateral institutions and mechanisms that govern their relationship in the twentieth century. The authors then explore the World War and Cold War alliance based on economic interest and shared anti-Communist that made Canada part of a "new American empire." The years from 1960 until 1984 most merit their subtitle, Ambivalent Allies, as it was then that this continental consensus fragmented. In 1984 the relationship was restored as Canada's Conservative government embraced the United States with an ardour that stunned a Canadian body politic nurtured on the milk of anti-Americanism. The authors consider the economic and social dimensions of the relationship, from Canadian responses to the increasing weight of the U.S. cultural presence, to the archaic stereotypes through which Canadians and Americans understand each other. They conclude that while Canadians have been obsessed with the United States, Canada has been a matter of consuming disinterest to the United States public and to most of its leaders. Despite the oft-repeated platitudes about a "special relationship" between the two countries, the authors maintain that what is striking is the extent to which U.S. policy toward Canada conforms to U.S. policy toward the rest of the world. For its part, Canada's preoccupation with the United States has shaped Canadian national policies. Any apparent contemporary trend toward consensus and convergence between the United States and Canada, they conclude, must be viewed through the lens of two centuries of ambiguity and ambivalence.