This book explores the ideas of Tadeusz Kowalik, demonstrating their continued relevance in the modern world, particularly with regard to his work on capitalism and socialism. Providing insight into his life, economic ideas and political activities, it also examines his engagement with the work of Rosa Luxemburg, Michal Kalecki and Oskar Lange. By highlighting his analysis of contemporary issues, the book establishes a link between his work on political economy and public sector reform, particularly in relation to the health system and pensions. The book also examines Kowalik's analysis of different economic systems and the structural transformation of twentieth-century economies. It will be of interest to students and researchers of political economy and the history of economic thought.