This course provides an introduction to how markets operate, the criteria for assessing their performance, and the circumstances under which they perform well or poorly. The first half of the course covers skills for predicting market behavior including supply and demand and the strategies of consumers and firms. The second half examines the rationale for government intervention in markets including problems of information, monopoly, externalities and collective or public goods. No prior exposure to economics is required and applications to urban planning are stressed. This course is also offered at the Kennedy School as API-105B.