Volume 45 of "Progress in Drug Research" contains eight reviews and the various indexes which facilitate its use and establish the connection with the previous volumes. The articles in this volume deal with neuro peptides as native immune modulators, with Calmodulin and with effects of cell stimuli and drugs on cellular activation, with recent advances in benzodiazepine receptor binding studies, with the medicinal chemistry and therapeutic potentials of ligands of the histamine H3 receptor, with Serotonin uptake inhibitors, with computer-aided drug design, with natri uretic hormones and with the recent developments in the chemotherapy of osteoporosis. In the 36 years that PDR has existed, the Editor has enjoyed the valu able help and advice of many colleagues. Readers, the authors of the reviews and, last but not least, the reviewers have all contributed greatly to the success of this series. Although the comments received so far have generally been favorable, it is nevertheless necessary to analyze and to reassess the current position and the future direction of such a series of monographs. So far, it has been the Editor's intention to help disseminate information on the vast domain of drug research, and to provide the reader with a tool with which to keep abreast of the latest developments and trends. The reviews in PDR are useful to the nonspecialist, who can obtain an overview of a particular field of drug research in a relatively short time."