The standard rationality hypothesis implies that individualbehaviour can be represented as the maximization of a suitablyrestricted utility function. This hypothesis lies at the heart of alarge body of economics, of course, but also in political science, ethics, and other major branches of the social sciences. Though thishypothesis of utility maximization deserves our continued respect, finding further refinements and developing new critiques remain areasof active research.The main purpose of the "Handbook of Utility Theory" is to makemore widely available some recent developments in the area. Theeditors selected a list of topics that seemed ripe enough to becovered by review articles. Then they invited contributions fromresearchers whose expert work had come to their attention. So the listof topics and contributors is largely the editors' responsibility.Each contributor's chapter has been refereed, and revised according tothe referees' remarks.Whereas Volume I of the "Handbook of Utility Theory"is largelyconcentrated on basic theory, the present volume is concerned withextensions and applications to other branches of economic theory.Taken together, these first two volumes contain all the purelytheoretical material that the editors planned to cover. The chapterson experimental and empirical research on utility and the chapters onthe history of utility theory will appear in Volume III.