Up to this point, we have been describing the U.S. banking system and how it works. To fully understand that system, however, it is helpful to understand how and why it was created—a story that is closely intertwined with the story of how and when things went wrong. The key elements of twenty-first-century U.S. banking weren’t created out of thin air: efforts to change both the regulations that govern banking and the Federal Reserve system that began in 2008 have propelled financial reform to the forefront. This reform promises to continue reshaping the financial system well into future years.