This selection of key texts from Roberto Mangabeira Unger’s three-volume Politics presents an explanatory theory of society and a program for social reconstruction as a radical alternative to Marxism and social democracy. The explanatory part of the work rejects the search for a lawlike science of society and history, and emphasizes the haphazardness and replaceability of existing social arrangements. Unger shows how such an antideterministic approach can inspire surprising explanations of past and present institutions, with the result that our sense of the possible is both broadened and refined. He then shows how we can rebuild our political, economic, and social institutions, making them more faithful to the experimental nature of democracy. The consequence is to redefine the focus for ideological debate and institutional innovation throughout the world, in developed and developing countries alike. With an introduction that locates Unger’s work in the history of politics and social theory and explores its major themes, this selection will confirm Geoffrey Hawthorn’s description of Politics as the most powerful social theory of the second half of the twentieth century.