The subject of the monograph focuses on the issue of raison d'état in contemporary political thought of parties competing with each other in the Polish political arena since 2001. The cognitive goal of the book was to determine the content and scope of the meaning of the political science category of raison d'état, which was treated as a category of political thought and analyzed by reconstructing the views of the main political parties in Poland on such issues as: state, sovereignty, political identity, political system, social order, economy and foreign policy and security. The monograph contains the latest results of scientific research based on Polish and foreign literature on the subject and source materials primary for the ideological trends of contemporary Poland.