This volume contains the Proceedings of the 25th Mosbach Colloquium, the general theme of which is the Biochemistry of Sensory Functions. It was intended, continuing the silver-tradition of these Colloquia, to provide the uninitiated biochemist with an insight into the current status of a line of research in Molecular Biology which, more than many other fields in Biochemistry, has maintained its contacts with and respect for Physiology. The speakers were asked to attempt to outline their topic sufficiently to define the fundamentals and to build up upon this basis the more sophisticated details of their own studies. It is for the reader to evaluate how well both organizer and participants 1 have attained this end . These Proceedings not only mirror the hubs around which several groups of scientists wheel but may also serve as a source of literature references and for the advanced student as an introduction to this highly up-to-date branch of Biochemistry, although no index is provided as the table of con­ tents is considered sufficient to locate most of the s,