Volume 31 of "Progress in Drug Research" contains 13 articles, a sub ject index, an index for all articles that have been published so far in this series of monographs, as well as an author and subject index for all 31 volumes. The reviews in this volume are particularly concerned with the therapy of helminth diseases, with pyramidinones as biody namic agents, and with quinolones which are of interest in the treat ment of infections. For a deeper understanding of the pharmacokinet ic actions of modem drugs, the articles on cooperative binding of drug molecules to DNA, on in vitro models for the study of antibiotic activi ties, on inhibitors of the renin-angiotensin system, on GAB A-drug in teractions, and on the mechanism of action of anxiolytic drugs provide a wealth offacts and new findings. The pharmacology of caffeine is re viewed from the viewpoint of its role in combination with other phy siologically active substances, and the chapter on high resolution nuc lear magnetic resonance spectroscopy demonstrates the importance of this method in the development of new drugs. Finally, the article on light and dark touches border problems of the therapy of psychic dis orders. With these contributions, the authors aim to summarize latest achieve ments in important and actual fields of drug research. Researchers who are actively engaged in the same or in similar fields of research are sure to benefit from these efforts.