"Today, classical political economy is often identified by contemporary economists with the quantity theory of money and the so-called “doctrine of free trade,” but historically there was in fact a large and variable set of positions on both within the classical orbit. And, in contrast to Marx's characterization of its scope and origins, the beginnings of a systematic classical political economy have been associated first and foremost with the work of the eighteenth-century Scottish philosopher, Adam Smith. In terms of illuminating our understanding of the significance of classical political economy for the history of political thought, its origins are identified with the time period roughly between 1750 and 1867, and with a group of economic thinkers drawing upon and revising Smith's Wealth of Nations as a basis for analyzing the production, distribution, and exchange of commodities in the market of commercial society, and later within industrial capitalism."