The English edition of this book has been prepared from the third Gem1an edition published in December 1974. The first two German editions, published in 1971 and 1972, respectively, were very well received in Germany. We hope that this English version will enjoy a similar popularity by students wishing to understand the essential concepts relevant to the fascinating field of neurophysiology. The evolution of this book has been unique. The first edition was based on a series of lectures presented