Bruce Corman Norbert Greenwald, born August 15, 1946, is an American economist and professor of finance and economics at Columbia Business School. He is a renowned authority on value investing, productivity, and the economics of information, described by The New York Times as 'a guru to Wall Street's gurus.' Prior to joining Columbia in 1991, he worked as a research economist at Bell Laboratories and Bell Communications Research, and served as an assistant professor at Harvard Business School. He holds the position of Robert Heilbrunn Professor Emeritus of Finance and Asset Management, where he also acts as the academic director of the Heilbrunn Center for Graham & Dodd Investing, and serves as an advisor at First Eagle Investment Management. Greenwald has authored key books including 'Value Investing: from Graham to Buffett and Beyond' and 'Competition Demystified: A Radically Simplified Approach to Business Strategy.'