OPTIMAL MONETARY POLICY: WHAT WE KNOW AND WHAT WE DON'T KNOW*

In this article, I examine the current state of knowledge about optimal monetary policy. I distinguish between two literatures, basic and applied. The basic literature is explicit about the frictions that generate a positive value for money and make it socially beneficial. The applied literature is not. I describe the recent lessons about monetary policy that we have learned from each literature and discuss how the two distinct approaches may be usefully combined.