William Baumol made seminal contributions in many areas of economics, in understanding externalities, the economics of performing arts, entrepreneurship, and the notion of fairness, to name a few. He identified the “cost disease” of rising relative costs of services such as education, healthcare, and opera singing, where the human component is the key to the delivery of the service. Baumol had a profound understanding of the history of economic thought that sought to explain the real world.