I have spent my entire adult life studying and writing about the United States in world affairs. Much of my work, especially the essays, but also many of the books, were written for other historians and perhaps graduate students. But, I always felt the need to write for a larger audience. Many years ago, the late Barbara Tuchman, a wonderful popular historian, wrote to compliment me on a review I wrote savaging an absurd biography of General George Marshall authored by a popular biographer. She noted, however, that books like that one, would always win public attention so long as professional historians wrote primarily for each other. I never forgot her admonition, and several of my books, especially my America’s Response to China , were written for undergraduates and the general public. This book falls into that category. I left out the footnotes and bibliography, the usual apparatus of scholarship, noting where the interested reader could find them (see George Herring’s From Colony to Superpower or the New Cambridge History of American Foreign Relations for which I was the general editor—both over 1,000 pages).I have always enjoyed taking long and complicated arguments and cutting them down to size and removing unnecessary complications. Some years ago, I wrote East Asia at the Center: Four Thousand Years of Engagement with the World in less than 500 pages. I imagined I could write a history of American foreign relations in 200 pages. I failed: this book runs 299 pages.