The purpose of this class is to bring together students and interdisciplinary experts in Computer Science and Finance to discuss the emerging area of Decentralized Finance (or DeFi). DeFi has experienced an unprecedented growth, with hundreds of projects and a countless stream of financial, distributed systems, and blockchain innovations. The total value locked (TVL) in decentralized finance — a measure of the total value of assets committed to the DeFi ecosystem — has reached over $80 billion. When compared to the traditional centralized finance (CeFi), DeFi offers products and services serving similar financial goals, but critically innovates with novel capabilities such as instantaneous multi-billion USD flash loans. By utilizing blockchain and smart contract technologies, DeFi as a whole aims to provide a new platform for programmable, automated finance services that remove the reliance on central trust and intermediaries. Our goal is to provide a framework to understand this new area of financial services. For each finance function, we will consider 1) the current intermediated structure, and then b) the DeFi version (actual or proposed) that fulfills the function. Is either one of these optimal? We will evaluate both through the lens of CS and finance. Is the application computable (efficiency, decidable), programmable (automatic)? Is the application welfare-enhancing and stable (not a source of systemic risk). How do the new and old systems interact? We aim for the students to be able to critically evaluate whether a new DeFi protocol is novel and practical. We further will capture the security danger in DeFi, as well as their impact on the underlying consensus security. Lastly, we hope to give an insight into how to program and structure secure and incentive-compatible DeFi applications.