Theories of Surplus Value (German: Theorien über den Mehrwert) is a draft manuscript written by Karl Marx between January 1862 and July 1863.[1] It is mainly concerned with the West European theorizing about Mehrwert (added value or surplus-value) from about 1750, critically examining the ideas of British, French and German political economists about wealth creation and the profitability of industries.[2] At issue are the source, forms and determinants of the magnitude of surplus-value,[3] and Marx tries to explain how, after failing to solve basic contradictions in its labour theories of value, the classical school of political economy eventually broke up, leaving only "vulgar political economy" which no longer tried to provide a consistent, integral theory of capitalism, but instead offered only an eclectic amalgam of theories which seemed pragmatically useful or which justified the rationality of the market economy.[4]