The dominant theory of economics from the eighteenth century until superseded by neoclassical economics in the twentieth century. It is associated with Adam Smith's Wealth of Nations (1776) John Stuart Mill's Principles of Political Economy (1848), and the work of David Ricardo (1772-1823), who were the first to systematically establish a body of economic principles. The basic idea was that the economy functioned most efficiently if everyone was allowed to pursue their own self-interest. Classical economics therefore favoured laissez faire; the primary economic law was that of competition.