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.