Abstract: This paper reviews and critically evaluates the empirical literature on the effects of U.S. unconventional monetary policy on both financial markets and the real economy. In order to understand how such policies could work, we also briefly review the literature on the theory of such policies. We show that event studies provide very strong evidence that U.S. unconventional policy announcements have strongly influenced international bond yields, exchange rates, and equity prices in the desired manner. In addition, such studies indicate that such policies curtailed market perceptions of extreme events. Calibrated modeling and vector autoregressive (VAR) exercises strongly suggest that these policies significantly improved macroeconomic outcomes, raising U.S. GDP and CPI, through these changes in asset prices. Both event studies and VARs imply positive international spillovers of such policies.