The collection of papers presented in this special issue arose out of two events. The first was the symposium "Escaping Satiation - Increasing Product Variety, Preference Change and the Demand Side of Economic Growth" which was held at the Max Planck Institute in Jena, Germany, in December 1997. The Fritz Thyssen Foundation provided financial support for this seminal symposium which is gratefully acknowledged. Wilhelm Ruprecht was of great help in preparing the symposium and I would like to express my gratitude to hirn on this occasion. Many stimulating exchanges with hirn over the past few years while he was a research associate at the Institute working on long term changes in consumption convinced me of the relevance and importance of this problem for understanding modem economic growth. I also owe thanks to many people who encouraged me to go ahead with the symposium, among them Stanley Metcalfe, Carl Christian von Weizsäcker, and also Ehud Zuscovitch, who died so unexpectedly last year.