Bruce Greenwald is Professor of Finance and Economics at Columbia Business School. He researches market mechanisms, corporate finance, and managerial economics. Greenwald received a PhD in economics from MIT, an MPA and an MS in electrical engeering from Princeton, and a BS in electrical engeering from MIT. Greenwald served as Research Economist at Bell Laboratories for four years, and was Member of Technical Staff for Bell Communications until 1991. Major publications include "Adverse Selection in the Labor Market"; Review of Economics Studies; and the following with J. Stiglitz: "Examining Alternative Macroeconomic Theories"; Brookings Papers on Economic Activity; "Externalities in Economics with Imperfect Information and Incomplete Markets"; Quarterly Journal of Economics; "Imperfect Information, Credit Markets and Unemployment"; European Economic Review; and Expectations and Macroeconomics. "Money, Imperfect Information and Economic Fluctuations" ; and Expectations and Macroeconomics.