Economic conduct still continues to be somewhat mysterious to the economists; and they are forced to content themselves with adumbrations whenever the discussion touches this central, substantial fact. The Preconceptions of Economic Science is a three parts essay on the preconceptions held by different economists when they formulated their economic theories. Veblen summarizes the world views of famous economists from Adam Smith to Alfred Marshall and analyzes the influence of their respective world views on the development of economics. Thorstein Veblen was an American economist and social scientist who made important contributions to the study of economic institutions and the study of social class. He is best known for his book The Theory of the Leisure Class which introduced the term "conspicuous consumption".