Theorising Noumenal Power is a critical engagement with Rainer Forst’s theory of what he calls "noumenal power." Forst is the most significant younger generation critical theorist of the Frankfurt School, and his critics include several of the most influential contemporary political power theorists. The concept of noumenal power locates the sources of social and political power in the space of reasons or justifications – using a normatively neutral account of "justification." To exercise power, on that account, means to be able to determine, use, close or open up the space of justifications for others. Going back to Kant, the social subject is theorized as a reasoning being who confers legitimacy upon political structures based upon the cognitive faculty of justification. As argued by Max Weber, authority is the foundation of political institutions and authority presupposes a belief in legitimacy. On the one hand such beliefs can be distorted, as in ideology, or they can be based upon a process of reasoned justification relative to normatively desirable principles. Critiquing the former, while building upon the latter, serves as the foundation for theorising just democratic politic institutions. For Forst’s critics, a key theme is how to differentiate ideological (bad) justification, typically based upon emotion, from normatively right democratic reasoning. Other important themes are the analysis of structural domination or the use of threats or other means of exercising power. The debate in this volume constitutes an exciting new way of re-thinking the foundations of ideology, political power, democracy and justice. Providing a state-of-the-art discussion concerning the relationship between political power and justification Theorising Noumenal Power is essential for students and scholars interested in the theoretical foundations of political power, democracy and justice. The chapters were originally published in the Journal of Political Power.