This volume represents the proceedings of the 24th Mos bach Colloquium on "Regulation of Transcription and Trans lation in Eukaryotes" which was held April 26-28, 1973, in Mosbach, Germany, under the auspices of the Gesellschaft fiir Biologische Chemie. To the three of us (H. KERSTEN, P. KARLSON and myself) who were commissioned with the invitation of speakers, it was a difficult decision as to whether we should attempt to cover with some twenty contributions as many aspects of this broad topic as possible, or to sacrifice the intellectually perhaps more pleasing but more specula tive concepts and to concentrate on a few aspects of gene expression in reasonable detail. We unanimously decided on the latter course, leaving such important and timely topics as for example, hormone action, cyclic AMP and reverse transcription to the proceedings of other symposia, and con centrating on the four questions which are most basic to an understanding of the mechanisms of transcription and trans lation and for which fragmentary but nonetheless reliable experimental results have become available within the last few years. These are the structure of chromatin, the syn thesis of messenger RNA, the structure of the active ribo some, and the role of initiation factors in protein synthesis.

It is about 15 years since the first presentation on uteroglobin was given to a group of developmental biologists, reproductive physiologists, and geneticists who had gathered in November 1966 at Konstanz (Germany). In the following decade so much knowledge was accumulated that a special symposium seemed appropriate. This was organized as a satellite symposium to the International Congress of Endocrinology at Hamburg and brought together 50 scientists at Aachen. These scientists, working in the field of pro teins and steroids, in early pregnancy, recognized the impact of what had been reported, and many of them later agreed to contribute to this booN. and thus to present their research d, ta available until December 1980. The present volume covers a relatively broad spectrum of data and observations which shed some light on preimplantational embryonic life and on the supports and obstacles provided by the maternal organism with respect to final accomplishment of normal im plantation and establishment of pregnancy. The book will serve both as a textbook and as a scientific dictionary for Ph.D. students, postdoctoral fellows and advanced scientists working in this area. The course of early pregnancy depends very much on a proper balance of steroid hor mones, and the induction of protein synthesis by steroid hormones is one of the well known fundamental processes in cellular differentiation and embryonic development."

Das 18. Mosbacher Colloquium, uber welches der vorliegende Band berichtet, war den Wirkungsmechanismen der Hormone gewidmet. Es war die Idee der Veranstalter, in diesem Rahmen moglichst viele Aspekte des Problems zu zeigen; eine enzyklo- padische Vollstandigkeit hinsichtlich der zahlreichen Hormone wurde nicht angestrebt. Das ware bei der beschrankten Zeit auch unmoglich gewesen. Einen kurzen Uberblick uber den behandelten Themenkreis und den wissenschaftlichen Ertrag des Colloquiums habe ich im SchluBwort gegeben. Sinn eines Colloquiums ist das Gesprach, die Diskussion; der Vortrag solI nur die Basis dazu liefern. In diesem Sinne haben wir auch im vorliegenden Band der Diskussion einen breiten Raum eingeraumt, und ich glaube, daB manche dieser Diskussionsbemer- kungen die Vortrage erheblich erganzen und vertiefen. Die Organisation der Veranstaltung lag weitgehend in den Randen von Herrn Professor Dr. AUHAGEN. Die Tonbandaufnah- men der Diskussion, die fur die schriftliche Fixierung der Dis- kussion von besonderer Bedeutung waren, wurden in technisch Herrn Dr. WINTER, Stuttgart, besorgt; hervorragender Weise von die hohe Qualitat dieser Aufzeichnungen hat meine Arbeit als Herausgeber sehr erleichtert, und ich mochte Herrn Dr. WINTER deshalb auch an dieser Stelle danken. - Weiterhin gilt unser aller Dank den Vortragenden sowie den Diskussionsrednern, die zum Gelingen des Colloquiums beigetragen haben, insbesondere auch unseren Gasten aus dem europaischen Ausland und den USA.