History of economic thought died, Engels completed the second volume of "Das Kapital" from his notes. Marx wrote his magnum opus "Das Kapital" (1867) at the British Museum's library in London. Karl Marx begins with the concept of commodities. Before capitalism, says Marx, production was based on slavery – in ancient Rome for example – then serfdom in the feudal societies of medieval Europe. The current mode of labor exchange has produced an erratic and unstable situation allowing the conditions for revolution. People buy and sell their labor as people buy and sell goods and services. People themselves have become disposable commodities. As Marx
Karl Marx value advocated by David Ricardo. The work was enthusiastically received, and the edition sold out quickly. The successful sales of "A Contribution to the Critique of Political Economy" stimulated Marx in the early 1860s to finish work on the three large volumes that would compose his major life's work – "Das Kapital" and the "Theories of Surplus Value", which discussed the theoreticians of political economy, particularly Adam Smith and David Ricardo. "Theories of Surplus Value" is often referred to as the fourth volume of "Das Kapital" and constitutes one of the first comprehensive treatises on the history of economic thought.