This chapter examines the neglected epistemology of markets. It argues that we often get useful information from markets concerning popularity and incentives, and that these should inform our decision-making. The popularity of a service provider despite being located in a dangerous neighborhood or being considered unattractive, for example, is an important signal that should guide our thinking. So should the incentive structure a service provider faces, for instance, whether he or she can take customers for granted or not. Both constitute evidence that we are likely to receive comparatively good service, since their popularity comes despite marked disadvantages, and their incentive structure is aligned with our own aims as consumers. Applications include dining, art, education, and law.