Nuclear Reactions explores the nuclear consensus that emerged in post–World War II America, characterized by widespread support for a diplomatic and military strategy based on nuclear weapons and a vision of economic growth that welcomed nuclear energy both for the generation of electricity and for other peaceful and industrial uses. Unease about the environmental consequences of nuclear energy and weapons development became apparent by the early 1960s and led to the first challenges to that consensus.The documents in this collection address issues such as the arms race, “mutually assured destruction,” the emergence of ecosystems ecology and the environmental movement, nuclear protests, and climate change. They raise questions about how nuclear energy shaped—and continues to shape—the contours of postwar American life. These questions provide a useful lens through which to understand the social, economic, and environmental tradeoffs embedded within American choices about the use and management of nuclear energy.