During the last annual meeting of the Austrian Society for Electron Microscopy it was decided to organize scientific symposia dealing with basic problems of cytology. If possible such symposia should be arranged in cooperation with other scientific societies. We intended to arrange symposia on special fields, to be presented on several aspects by excellent scientists invited. Neural Transmission was chosen as a central topic for this first symposium. The subject represents a most rapidly expanding field of research and is of particular interest to morphologists, physiologists, pharmacologists, biochemists and clinicians. We are indebted to all the invited speakers for contributing their interesting papers. I feel bound to thank once more the firm of Bender, a subsidiary company of Boehringer Ingelheim and of Arzneimittelforschung Ges. m. b. H. Wien, for the generous financial support which made possible to realize the symposium. The publication of this volume, representing the papers and discussions originally read at the symposium and elaborated by the authors in detail and more extensively, was only made possible by the generous cooperation of the Springer-Verlag Vienna.