This book explains the inherent contradictions of Marxist economic theory and how they became apparent when the theory was applied in practice. It introduces the main theories and authors of Marxist economic thought, explores its implementation in the Soviet Union and the People's Republic of China, and offers a comparative analysis of the main distinctive features of socialist and capitalist economic systems. In turn, the book provides answers to the following questions: What has happened to the "socialist reality" and why has it become unacceptable for society? What are the causes of the collapse of the socialist economic system? This book appeals to scholars and students of economics and anyone interested in Marxist economic thinking and the practice of socialism.