The NBER Macroeconomics Annual provides a forum for important debates in contemporary macroeconomics and major developments in the theory of macroeconomic analysis and policy that include leading economists from a variety of fields. The papers and accompanying discussions in NBER Macroeconomics Annual 2009 address how heterogeneous beliefs interact with equilibrium leverage and potentially lead to leverage cycles, the validity of alternative hypotheses about the reason for the recent increase in foreclosures on residential mortgages, the credit rating crisis, quantitative implications for the evolution of the U.S. wage distribution, and noisy business cycles.About the Author: Daron Acemoglu is the Charles P. Kinderberger Professor of Applied Economics at the Massachusetts Institute of Technology and a research associate of the NBER. Michael Woodford is the John Bates Clark Professor of Political Economy at Columbia University and a research associate of the NBER.