This sharp and engaging book by leading governmental scholar Cass R. Sunstein examines dramatically shifting understandings of what's normal-and how those shifts account for the feminist movement, the civil rights movement, the rise of Adolf Hitler, the founding itself, political correctness, the rise of gun rights, the response to COVID-19, and changing understandings of liberty. Prevailing norms include the principle of equal dignity, the idea of not treating the press as an enemy of the people, and the social unacceptability of open expressions of racial discrimination. But norms can turn upside-down in a hurry. What people tolerate, and what they abhor, depends on what else they are seeing. Exploring Nazism, #MeToo, the work of Alexander Hamilton and James Madison, constitutional amendments, pandemics, and the influence of Ayn Rand, Sunstein reveals how norms change, and ultimately determine the shape of society and government in the United States, Europe, and elsewhere.