This chapter explains the essential elements of Marxist economics or, preferably, Marxist political economy (MPE). This analysis provides the foundation for Marx's systemic critique of capitalism and his conclusion that the contradictions and limitations of this exploitative mode of production could be overcome only through the transition to a new mode, communism, through revolution if necessary. In principle, MPE offers the strongest intellectual threat to the mainstream as well as supporting the most acute political challenge to capitalism. MPE takes social classes, rather than individuals, as its starting point for understanding the nature of the economy both historically and socially. Marx called 'commodity fetishism' the limitation of the understanding of commodities to the surface relations between price and use as opposed to labour and other invisible relations by which commodities come to the market. Neoclassical economic theory defines capital as an ensemble of things, including means of production, money and financial assets.