Through an extensive examination of the conceptions of social justice that may be ascribed validly to Karl Marx’s political thougtht, Elliot R. Pruzan analyzes the apparent conflict between Marx as value-neutral social scientist and as revolutionary. He suggests a resolution to this conflict through a carefully constructed presentation of Marx’s theory of human nature and the ethical presuppositions of that theory. In so doing, Pruzan identifies those elements of Marx’s political thought that warrant our continued serious consideration of it as a genuine theory of politics, especially when compared with other more traditionally conceived forms of political thought.