The idea to publish a Handbook of Economic Psychology came up as a natural consequence of a discussion concerning appropriate reading material for courses in economic psychology. The discussion took place a few years ago in the Department of Economic Psychology at Tilburg University, The Netherlands. It was noted that there was a surprising lack of collections of pertinent readings, to say nothing about the lack of textbooks in the English language. So the present editors, who had been involved in the discussion, decided to start working on a Handbook. The situation has changed quite a lot since then. There are now a number of books, internationally available in the English language, in economic psy chology or behavioral economics. The interest in this field of study is expanding quite impressively. The Journal of Economic Psychology is now (1988) in its ninth volume and many other journals are publishing articles in the field. The application of psychological theories and methods to economic prob lems or the study of economic experiences and behavior is variously referred to as economic psychology or behavioral economics. While in principle we do not want to overdo the differences between the two, we have a feeling that economic psychology has a slightly stronger flavor of psychology than behavioral economics which in its turn seems to be closer to economics. Psychologists tend to feel more at home in economic psychology, while economists seem to favor behavioral economics.