The Theory of the Leisure Class: An Economic Study of Institutions (1899), by Thorstein Veblen, is a treatise of economics and sociology, and a critique of conspicuous consumption as a function of social class and of consumerism, which are social activities derived from the social stratification of people and the division of labor; the social institutions of the feudal period (9th–15th c.) that have continued to the modern era.Veblen discusses how the pursuit and the possession of wealth affects human behavior, that the contemporary lords of the manor, the businessmen who own the means of production, have employed themselves in the economically unproductive practices of conspicuous consumption and conspicuous leisure, which are useless activities that contribute neither to the economy nor to the material production of the useful goods and services required for the functioning of society. Instead, it is the middle class and working class who are usefully employed in the industrialised, productive occupations that support the whole of society. Source: Wikipedia (en)