Volume 23 includes six contributions as well as the Index for volumes 16-23. The key-word Index, like those of volumes II and IS, provides the reader with a simple cross-reference to all fields of possible interest, making this series of monographs even more useful as an encyclopaedic reference work. The scientific articles treat various topical areas of drug research, reviewing developments and indicating unsolved problems. The editor hopes to have provided the reader with a useful orientation and reference work. Experience over the last few years has shown that a more rapid publica- tion of the individual volumes better meets the wishes of readers by keeping pace with the speed of modem research. The present volume, as well as its predecessor, has broken the tradition of 500-600-page volumes in the hope of better satisfying the needs of the readers of this series. Finally, thanks are due to all those who have provided helpful criticism of past volumes, thereby providing valuable advice regarding the form of future volumes, and to Dr. A. Niif for his careful revision of the manu- scripts and correction of the proofs. Thanks are also due to the publish- ers and printers Birkhiiuser, in particular Messrs. Th. Birkhiiuser and C. Einsele. July 1979 Dr. E. Jucker Sandoz Ltd., Basel Vorwort Der 23. Band umfasst sechs Beitrage nebst dem Index der Bande 16-23.