Reserve army of labour in the context of "Das Kapital"

Capital: A Critique of Political Economy (German: Das Kapital. Kritik der politischen Ökonomie), also known as Das Kapital (German: [das kapiˈtaːl]), is a foundational theoretical text in Marxist philosophy, economics, and politics by Karl Marx. His magnum opus, the work is a critical analysis of political economy, meant to reveal the economic patterns underpinning the capitalist mode of production. Das Kapital is in three volumes, of which only the first was published in Marx's lifetime (1867); the others were completed from his notes and published by his collaborator Friedrich Engels in 1885 and 1894.

The central argument of Das Kapital is that the motivating force of capitalism is in the exploitation of labour, whose unpaid work is the ultimate source of surplus value and profit. Beginning with an analysis of the commodity, Marx argues that the capitalist mode of production is a historically specific system where social relations are mediated by commodity exchange. He posits a labour theory of value, contending that the economic value of a commodity is determined by the socially necessary labour time required for its production. Under this system, the worker's capacity to labour (their labour power) is sold as a commodity, but its use-value—the ability to create new value—is greater than its exchange-value (the wage), allowing the capitalist to extract surplus value. This process drives capital accumulation, which in turn fosters technological change, the creation of a reserve army of labour, and a long-term tendency of the rate of profit to fall, leading to economic crises and intensifying class conflict.