Economics wealth (capital) and a constant population size. Marxist (later, Marxian) economics descends from classical economics. It derives from the work of Karl Marx. The first volume of Marx's major work, "Das Kapital", was published in German in 1867. In it, Marx focused on the labour theory of value and the theory of surplus value which, he believed, explained the exploitation of labour by capital. The labour theory of value held that the value of an exchanged commodity was determined by the labour that went into its production and the theory of surplus value demonstrated how the workers only got paid
Value product only to the net output of "capitalist" production, not to the valuation of "all" production in a society, part of which may of course not be commercial production at all. The concept is formulated more precisely when Marx considers the reproduction and distribution of the national income (see e.g. his manuscript called "Results of the Immediate [or Direct] Process of Production", available in English in the Pelican edition of "Das Kapital"), and also online; and the last chapters of "Das Kapital" Volume 3). Marx wrote this in 1864, i.e. about 70 years or so before the first comprehensive Gross National