A Contribution to the Critique of Political Economy (German: Zur Kritik der Politischen Ökonomie) is a book by Karl Marx, first published in 1859. The book is mainly an analysis of capitalism and quantity theory of money,[1] achieved by critiquing the writings of the leading theoretical exponents of capitalism at that time: these were the political economists, nowadays often referred to as the classical economists; Adam Smith (1723–90) and David Ricardo (1772–1823) are the foremost representatives of the genre.