Forty thousand years ago, humans began to embrace the art of cooperation and mutual consensus. Since then, cooperation has remained central to cultures around the globe, enabling individuals to formulate and pursue life plans focused on collaboration rather than mere survival. This book challenges prevailing conceptions of freedom by developing a new theory rooted in our cooperative nature: freedom as social cooperation (FSC). This approach posits freedom beyond the absence of interference by others (negative freedom), a particular mental or material condition (positive freedom), or a form of independence (republican freedom). Freedom is a cooperative practice. The book presents FSC as an innovative conception of freedom and expands it into a theory of liberal democracy that accounts for its political and economic institutions. In an era marked by political confrontation and seemingly irreconcilable differences, FSC offers a timely framework for enriching liberal democracy—reminding us that true freedom is achieved by working together.