This proceedings volume of an international conference which took place in Essen in October 1997 brings together economists, mathematicians, and psychologists. Their contributions represent new research in the field of mathematical utility theory with an emphasis on its applications in the social sciences. Readers of this volume can inform themselves about novel results in mathematical utility theory and their significance for the social sciences. The contributions cover a spectrum of fields from topological methods in utility theory to the application of experimental methods to utility theory.