'Daniel Kahneman and the late Amos Tversky have started a new perspective on the traditional economic categories of choice, decision, and value. A series of experimental and empirical studies by them and others have rejected traditional economic assumptions of rationality. Even more importantly, these scholars have developed alternative generalizations with significant predictive power and have found empirical verification for them. This outstanding collection of studies will make these new results widely accessible.' Kenneth J. Arrow, Joan Kenney Professor of Economics, Emeritus and Professor of Operations Research, Emeritus, Stanford University