This course aims to broaden one's perspective on markets and marketplaces. We learn how to design markets, institutions, and organizations in practice, and analyze their allocative properties, induced incentives, and limitations, to help formulate regulatory policy. The course underscores practical takeaways in designing a wide range of markets, e.g., auctions for procurement and spectrum allocation, matching markets to assign students to schools, doctors to hospitals, and resettle refugees, centralized versus decentralized labor markets for civil servants, online market platforms... We cover issues like fairness, efficiency, simplicity, transparency, externalities, strategyproofness, collusion, corruption, and affirmative action. Roughly half our time is focused on designing auction markets while the other half is focused on designing matching markets.