We describe some of the main features of the recent vintage macroeconomic models used for monetary policy evaluation. We point to some of the key di¤erences with respect to the earlier generation of macro models, and highlight the insights for policy that these new frameworks have to o¤er. Our discussion emphasizes two key aspects of the new models: the signi…cant role of expectations of future policy actions in the monetary transmission mechanism, and the importance for the central bank of tracking the natural levels of output and the real interest rate. We argue that both features have important implications for the conduct of monetary policy. In the 1980s and 1990s, many central banks continued to use reduced form statistical models to produce forecasts of the economy that presumed no structural change, but they did so knowing that these models could not be used with any degree of con…dence to generate forecasts of the results of policy changes. Thus, monetary policy-makers turned to a combination of instinct, judgment, and raw hunches to assess the implications of di¤erent policy paths for the economy. Romer (1991)). The models of this literature, however, were typically static and designed mainly for qualitative as opposed to quantitative analysis.By contrast, real business cycle theory, which was developing concurrently, demonstrated how it was possible to build quantitative macroeconomic models exclusively from the "bottom up"-that is, from explicit optimizing behavior at the individual level (e.g. Prescott (1986)) These models, however, abstracted from monetary and …nancial factors and thus could not address the issues that we just described. In this context, the new frameworks re ‡ect