This chapter provides an overview of the way in which Marxist theory developed since Marx's death in 1883. It outlines Karl Marx's own theory, specifically by splitting it into three overriding themes philosophy, political economy, and politics. The chapter focuses on the way in which it developed into the various schools of Marxism throughout the twentieth century. According to Vladimir Illich Lenin, the Marxist doctrine is essentially an amalgamation of classical German philosophy, classical English political economy, French socialist theory and revolutionary doctrines in general. Western Marxism was characterised by an attempt to free itself from the dogma of dialectical materialism, particularly with respect to its views regarding the inevitability of capitalist collapse and victory of the working class. Both structuralism and post-structuralism questioned many of Marxism's central theoretical and political claims, whether being the existence of a historically foundational revolutionary subject or, behind that, the idea that history could be made intelligible through philosophy.