Thorstein Veblen (1857-1929), the controversial American economist and social critic, argues that economics is essentially a study of the economic aspects of human culture, which are in a constant state of flux. In his best-known work, "The Theory of the Leisure Class" (1899), Veblen appropriated Darwin's theory of evolution to analyse the modern industrial system. While industry itself demanded diligence, efficiency, and co-operation, businessmen in opposition to engineers and industrialists were only interested in making money and displaying their wealth in what Veblen coined 'conspicuous consumption'. Veblen's keen analysis of the psychological bases of American social and economic institutions laid the foundation for the school of institutional economics.