The early Marx called for the "realization of philosophy" through revolution. Revolution thus became a critical concept for Marxism, a view elaborated in the later praxis perspectives of Lukács and the Frankfurt School. These thinkers argue that fundamental philosophical problems are, in reality, social problems abstractly conceived. Originally published as Lukács, Marx and the Sources of Critical Theory, The Philosophy of Praxis traces the evolution of this argument in the writings of Marx, Lukács, Adorno and Marcuse. This reinterpretation of the philosophy of praxis shows its continuing relevance to contemporary discussions in Marxist political theory, continental philosophy and science and technology studies.