Samuel Moyn, a Yale historian best known for his work on the history of human rights, argues that twentieth-century liberalism took a wrong turn during the Cold War and has been suffering the consequences ever since. The classical liberalism of the eighteenth and nineteenth centuries, in Moyn's telling, was confident, progressive, and ambitious: it imagined human emancipation, the dismantling of inherited hierarchies, and the moral improvement of societies. The 'Cold War liberalism' that emerged in response to Stalinism—associated with thinkers such as Isaiah Berlin, Karl Popper, Judith Shklar, Lionel Trilling, Hannah Arendt, and Gertrude Himmelfarb—was, by contrast, defensive and tragic. It distrusted utopian projects, narrowed the scope of liberty to protection against state coercion, and treated history as a series of dangers rather than possibilities. Moyn contends that this defensive turn cut liberalism off from the resources it needed—Enlightenment universalism, a serious account of equality, a commitment to creative human agency—and helped produce the listless, brittle liberalism of the post–Cold War era. The book is short, polemical, and tightly argued, drawing on close readings of the figures named above. It has been controversial: critics charge Moyn with caricature, while admirers see it as a long-overdue effort to reopen the question of what a more ambitious liberal politics might look like.