I began this book shortly after finishing a volume on Anglo–American economic diplomacy of the 1920s. That volume, which dealt in part with the diplomacy of European reconstruction following the First World War, stimulated my interest in the Marshall Plan to rebuild Western Europe after the Second World War. A history of the Marshall Plan seemed appropriate for other reasons as well. Although the plan was widely regarded as one of the most important international initiatives of the recent period, no thoroughgoing account of it existed at that point, only studies that treated its origins in 1947 and 1948. Then too, documents pertaining to the plan were just becoming available in the United States and in Great Britain. The availability of British documents was particularly important, in part because of my continuing interest in Anglo–American relations, in part because the British played a role second only to the Americans in the operation of the plan. These documents, notably the Bevin and Attlee papers, the Cabinet records, and the multiple files of the British Treasury and Foreign Office, have made it possible to write with some assurance about Whitehall's policy toward Western Europe, thereby filling a gap in the postwar history of British diplomacy. Much the same can be said of the memoirs, diaries, and published accounts by participants in the continental countries as well as in Great Britain. Together, they enriched my understanding of the political, economic, and security imperatives that influenced America's partners in Western Europe.