Karl Marx was a German-born philosopher, economist, political theorist, historian, sociologist, journalist, and revolutionary socialist. His best-known works are the 1848 pamphlet The Communist Manifesto and the three-volume Das Kapital (1867–1894); the latter employs his critical approach of historical materialism in an analysis of capitalism and is the culmination of his intellectual efforts. Marx's ideas and theories and their subsequent development, collectively known as Marxism, have exerted enormous influence on modern intellectual, economic and political history.

Revolutionary socialism is a political philosophy, doctrine, and tradition within socialism that stresses the idea that a social revolution is necessary to bring about structural changes in society. More specifically, it is the view that revolution is a necessary precondition for transitioning from a capitalist to a socialist mode of production. Revolution is not necessarily defined as a violent insurrection; it is defined as a seizure of political power by mass movements of the working class so that the state is directly controlled or abolished by the working class as opposed to the capitalist class and its interests.