In the period between 1918 and 1941, the years separating American involvement in the two world wars of this Century, the United States emerged as the preeminent global power. Significantly, this occurred despite the supposed isolation of the United States from international political affairs in those two decades. Involvement in international economic and financial affairs, however, was another matter. Since the mid-1940s, America's rise to preeminence has been an issue of enduring interest to scholars of international history, in general, and of American foreign relations, in particular. And although recent international historians have focused most of their attention on the period since 1941 and especially on the Cold War, the interwar period has retained a fascination for a sizable group of scholars. Coupled with recent efforts to address criticisms made by social and economic historians and others of that ilk, this fascination has led to the emergence of a more rigorous analysis of these pivotal years in the history of American foreign relations. As a consequence, older issues have been reexamined, newer ones have been assessed for the first time, and different interpretations, some at decided variance with one another, have emerged about how and why the United States achieved its preeminence. This is not to say that lacunae do not exist; they do. But American foreign relations in the interwar period are now recognized as more complex than previously imagined, and as integral to a distinct phase of historical development that was more than just prologue to what Henry Luce proclaimed in 1941 as the dawning of “the American Century.” The debate that has emerged since the late 1970s shows the vibrancy of not only this particular area of concern but also that of international history in general.

The crucial point to consider in this is that the study of American foreign relations in the interwar period is no longer the exclusive province of American scholars. Indeed, this aspect of modern American history knows no boundaries. As the United States achieved global power Status by 1945, extra-American interest in American foreign relations increased markedly, especially among international historians in Britain and Continental Europe and, within the remnants of the old British Empire, Australia and Canada. It is unfortunate that until recently American scholars have not made much use of the work of their non-American counterparts.