John W. Pratt is a professor of business administration, emeritus, at Harvard Business School. He was educated at Princeton and Stanford, specializing in mathematics and statistics. Except for two years at the University of Chicago, and a sabbatical in Kyoto on a Guggenheim fellowship, Pratt has been at Harvard for his entire professional career. Editor of the Journal of the American Statistical Association from 1965 to 1970, he is a fellow of five professional societies and has chaired National Academy of Sciences committees on environmental monitoring, census methodology, and the future of statistics. His recent research has been on risk aversion, risk sharing incentives, and the nature and discovery of stochastic laws, statistical relationships that describe the effects of decisions. He is co-author of a book entitled: Introduction to Statistical Decision Theory, published by MIT Press, 1995.