After World War II, the United States set about building a global order. Some historians believe this was an effort to balance against Soviet power. Others view the order as a modern empire, designed to make the world safe for American capitalism. Walker offers a third interpretation: the United States did want to spread its influence and the American way of life, but it did so by weaving other societies into a Pax Americana. This is the vision Walker sees in the Life owner Henry Luce’s famous 1941 call for “an American Century.” Walker provides an impressively detailed account of U.S. foreign policy in the early postwar decades, as the United States, in the words of Secretary of State Dean Acheson, learned how to “run the show.” Walker agrees with the historian Melvyn Leffler that the United States was driven by the need to protect itself against the illiberal and imperial projects that imperiled it. It sought “preponderance,” Walker says, but not “domination.” Walker closes his story with the presidency of Richard Nixon, when Americans feared that their century was already ending and the country was struggling to avoid decline.