Over the past five years, the US Federal Reserve has been engaged in an aggressive campaign to provide support to a US economy that was badly damaged by the financial crisis and the accompanying Great Recession. The Fed's efforts have included the massive provision of liquidity to impaired financial markets, the purchase of more than $3 trillion of long-term securities to ease overall financial conditions, and the issuance of forward guidance about the path of future short-term interest rates in order to lower borrowing costs across the yield curve. Although precise estimates of the effectiveness of these measures remain the subject of ongoing research, there can be little doubt that these policies have contributed to the process of repair and recovery of the US economy.