Volume 43 of "Progress in Drug Research" contains five reviews and the various indexes which facilitate its use and establish the connection with the previous volumes. The articles in this volume deal with high cholesterol blood levels and other dyslipidemias; search of ideal antihypertensive drugs; the natural PQlyamines and the immune system; biologically active quinazolones and with production and action of interferons. In the 35 years the PDR has existed, the Editor has enjoyed the valuable 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 review series. So far, it has been the Editors 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 non-specialist, who can obtain an overview of a particular field of drug research in a relatively short time. The specialist readers of PDR will appreciate the reviews' comprehensive bibliographies, and, in addition, they may even get fresh impulses for their own research. Finally, the readers can use the 43 volumes of PDR as an encyclopedic source of information.