Theorien über den Mehrwert
Marx first elaborated his doctrine of surplus value in 1857–58 manuscripts of "A Contribution to the Critique of Political Economy" (1859), following earlier developments in his 1840s writings. It forms the subject of his 1862–63 manuscript "Theories of Surplus Value" (which was subsequently published as "Capital, Volume IV"), and features in his "Capital, Volume I" (1867).