The concluding volume of Capital (Das Kapital) by Karl Marx, published posthumously and edited by Friedrich Engels. Building on the foundations laid in the first two volumes, Marx examines how surplus value is transformed into profit and how capitalism operates through competition, finance, interest, rent, and credit.

The book investigates the workings of the capitalist economy as a whole, including the role of banks, landlords, merchants, and industrial capitalists. It also discusses economic instability, falling profit rates, and the contradictions that Marx believed were inherent in capitalist systems.