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. In 1867, the first volume of "Das Kapital" was published, a work which analysed the capitalist process of production. Here Marx elaborated his labour theory of value, which had been influenced by Thomas Hodgskin. Marx acknowledged Hodgskin's "admirable work" "Labour Defended against the Claims of Capital" at more than one point in "Das Kapital". Indeed, Marx quoted Hodgskin as recognising the alienation of labour that occurred under modern capitalist production. No longer was there any "natural reward of individual labour. Each labourer produces only some part of a whole, and each part having no value or utility of itself, there is nothing on which the labourer can seize, and say: 'This is my product, this will I keep to myself'". In this first volume of "Das Kapital", Marx outlined his conception of surplus value and exploitation, which he argued would ultimately lead to a falling rate of profit and the collapse of industrial capitalism. Demand for a Russian language edition of "Das Kapital" soon led to the printing of 3,000 copies of the book in the Russian language, which was published on 27 March 1872. By the autumn of 1871, the entire first edition of the German-language edition of "Das Kapital" had been sold out and a second edition was published.