'The Theory of the Leisure Class' by Thorstein Veblen critiques the social and economic structures of capitalist societies, emphasizing the division between those who work and those who engage in conspicuous consumption and leisure. Veblen, an American economist and sociologist, introduces the concept of 'conspicuous consumption' to describe how the leisure class, through lavish spending, asserts its social status. This work is seminal in the study of economics and sociology, exploring themes of class, wealth, and social stratification.