Basic Economic Law of Capitalism, the production of maximum surplus value and its appropriation by capitalists through increasing the number of wage workers and intensifying their exploitation. "The directing motive, the end and aim of capitalist production,” Marx wrote, "is to extract the greatest possible amount of surplusvalue, and consequently to exploit labour power to the greatest possible extent" (K. Marx, Capital, Vol. I, p. 313). Discovered by Marx, the basic economic law of capitalism determines all the main features and aspects of capitalist production, its main stimulus and social tendency. It expresses the main production relation of the capitalist mode of production—that of the exploitation of wage labour by capital. Marx regarded the discovery of the law of surplus value to be the ultimate achievement of his studies in Capital. The formulation of the theory of surplus value and the discovery of the basic economic law of capitalism made it possible to explain almost all social and economic processes and phenomena in bourgeois society, reveal the profound foundations of the capitalist mode of production, its exploitative essence, and the reason of the antagonistic contradictions between the working class and the bourgeoisie. The theory of surplus value made it possible to scientifically substantiate the inevitability of socialist revolution and the collapse of the capitalist mode of production. That is why Lenin called the theory of surplus value the cornerstone of Marx’s economic teaching. He wrote that "Marx deduces the inevitability of the transformation of capitalist society into socialist society wholly and exclusively from the economic law of the development of contemporary society" (V. I. Lenin, Collected Works, Vol. 21, p. 71)—in other words from the law of surplus value. The basic economic law of capitalism operates throughout the entire period that this mode of production exists. But it has different forms at different stages of capitalist development. In the pre-monopoly epoch, it operated as the law of the average rate of profit. The transition to imperialism led to a modification of the law of surplus value into the law of monopoly profit (see Monopoly Superprofit).