Since 1978 this textbook, to the gratification of its authors and publisher, has found an undiminished readership. Recent research in sensory physiology has progressed so rapidly that this third edition, like the second, has required thorough revision. The understanding of pain, in particular, has increased to a remarkable degree. This development is reflected here in the appearance, for the first time, of a chapter devoted entirely to the subject "Nociception and Pain". In view of the great clinical significance of pain, it seemed necessary to broaden the scope of the discussion, so that in addition to the aspects directly related to sensory physiology consideration is given to the pathophysiology, pharmacology and psychology of pain. The chapters present in earlier editions have also been carefully reexamined and, where necessary, revised and extended. Most of the illustrations provided for the first edition by the Stuttgart studio Gay & Benz have been retained. Some required alteration or replacement, and a number of new illustrations have been added. For the meticulous skill with which she transformed our ideas into graphs and drawings, we are most grateful to Mrs. Regine Gattung-Petith.