The fourth volume of The Cambridge History of America and the World examines the heights of American global power in the mid-twentieth century and how challenges from at home and abroad altered the United States and its role in the world. The second half of the twentieth century marked the pinnacle of American global power in economic, political, and cultural terms, but even as it reached such heights, the United States quickly faced new challenges to its power, originating both domestically and internationally. Highlighting cutting-edge ideas from scholars from all over the world, this volume anatomizes American power as well as the counters and alternatives to 'the American empire.' Topics include US economic and military power, American culture overseas, human rights and humanitarianism, third-world internationalism, immigration, communications technology, and the Anthropocene.