In his best-known work, The Theory of the Leisure Class (1899), Veblen appropriated Darwin's theory of evolution to analyze the modern industrial system. While industry itself demanded diligence, efficiency, and cooperation, businesspeople - in opposition to engineers and industrialists - were interested only 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.