Since the first English edition of this book appeared three years ago, the authors have received many useful comments from readers. In preparing this amended edition we have carefully examined each chapter, improving and expanding the text where necessary; in the process, we have been greatly helped by their remarks. Further commentary on this edition will be much appreciated. Again, I should like to express the gratitude of all the authors to the staff of Springer-Verlag for expediting the publication of the book. Kiel, Germany, July 1981 ROBERT F. SCHMIDT Preface to the First Edition In the field of sensory physiology we are concerned with what our sense organs­ and the associated central nervous structures - can do and how that perform­ ance is achieved. Research here is not limited to description of the physi­ cochemical reactions taking place in these structures; the conditions under which sensations and perceptions arise and the rules that govern them are also of fundamental interest. Sensory physiology thus demands the attention of everyone who wishes to - or must - delve into the potentialities and limitations of human experience.