In September of 1977 scientists from many countries met at the Asticou Inn in Maine to present and discuss papers written especially for this monograph. The presentations were informal and directed to the special interests of the audience in order to generate discussions. The authors, many of whom are pioneers and leaders in their field, then had the oppor tunity to revise their contributions, which were brought together with the edited discussions to form this volume. The basic research studies presented here are important because of the essential role of gonadotropins in regulating the ovary and testis. This monograph will therefore be of interest to those concerned with fertility regulation, population control, possible new methods for contraception, and to those concerned with reproduction in domestic animals. Re searchers in other fields may find this monograph useful, as it has been de termined that gonadotropins are secreted by many tumors and are im plicated in many cancers. Human choriogonadotropin also seems to be found in most, if not all, cells of the human body. The significance of this, however, is unknown.