Since Bitcoin arrived on the scene in 2009, innovators have created thousands of cryptocurrencies — digital representations of tokens that reside on blockchains. Many view them as the future of money. But what is “money”? In this seminar, we will first explore the economic theory of money and the legal infrastructure that is required for its stability and proliferation. We will also examine the financial history of money to understand what happens when money is poorly designed: financial crises. These building blocks will allow us to assess digital assets like cryptocurrencies, stablecoins, and central bank digital currencies. We will focus on their implications for financial stability, monetary sovereignty, and national security, analyze proposed responses by Congress and financial regulatory agencies, and survey the evolving international landscape.