Understanding Inflation as a Joint Monetary-Fiscal Phenomenon

We develop the theory of price-level determination in a range of models using both ad hoc policy rules and jointly optimal monetary and fiscal policies and discuss empirical issues that arise when trying to identify monetary-fiscal regime. The article concludes with directions in which theoretical and empirical developments may go. The article is prepared for the Handbook of Macroeconomics, volume 2 (John B. Taylor and Harald Uhlig, editors, Elsevier Press).