Do our political systems and democracies really reflect the complex reality of the 21st century? Or does politics seem to be legislating about yesterday's world? In his latest book, Daniel Innerarity warns of the gap between the political concepts that serve as our guide and our overly complex reality that has long ceased to respond to them. Arguing that this theoretical deficit leads to a political practice that simplifies and impoverishes our democracies, nourishing the demagogues and sustaining reassuring old narratives, Innerarity proposes a modern update of key political concepts, from power and sovereignty to territory and representation. The theory of democracy originates from a time of relative social and political simplicity. There was less pluralism, less interdependence, political entities were autarkic, and the technological tools they had to handle had nothing to do with the sophistication of our artificial intelligence, our financial system, or the technological advances in medicine. And yet, Innerarity argues, there is no need to despair. If democracy has made the transition from the polis to the nation-state, from direct democracy to representative democracy, there is no reason to suppose that it cannot face new challenges, as long as it is provided with an adequate political architecture. Drawing on a broad range of sources, including classical and contemporary theorists, A Theory of Complex Democracy presents a new theory of democracy and government for the 21st century, a theory that starts from the premise that the most promising rejuvenation of our democracies is to make them more complex.