This class aims to show how the classical tools of price theory in the Marshallian tradition (supply, demand, externalities, monopoly, the short and long-term/Le Châtelier principle, the envelope theorem and the Cournot model) can be used to provide simple and elegant treatment a wide range of economic problems, including those considered to be on the “frontiers” of empirical and mathematical/theoretical microeconomics. Theoretical subject areas covered will include market, mechanism and auction design, behavioral economics, non-standard decision theory, industry dynamics, heterogeneity, rich (multidimensional, continuous type) principal-agent models, matching theory, bilateral bargaining, repeated games, redistribution, new approaches to social choice theory and public goods in large economies. Empirical studies we will consider will address issues including subjective well-being, cyclic patterns in cattle markets, the effects of railroads, the value of human life, experiments in auction markets, rationing in insurance markets, newspaper bias, the effects of entry on prices, global income inequality and the response of career choices to taxation. These tools will help us study policy issues including drug interdiction, occupational licensure, systems that allow students to bid for courses at university, climate change, sin taxes, regulating health care, designing auctions, merger approvals, criminal justice, optimal income taxation and new systems for voting.