This monograph contains a selection of papers presented at the Xlth World Congress of Fertility and Sterility (Dublin, 1983); the central theme is ovarian function and treatment of its disorders. Cross-cultural research provides international congresses with their unique quality due to the world-wide exchange of views; we think this aim has been achieved and reflected in this book. During the past decade significant advances have been made in our understanding of the events surrounding human ovulation leading to the development of an increasing range of effective therapeutic agents and the more logical use of existing drugs. As a result infertile patients with disordered ovulation can now anticipate a more favourable out- come. In addition more sophisticated diagnostic methods have revealed the presence of minor defects in ovarian function in some patients previously labelled as 'unexplained infertility'. The identification of such problems can only lead to further therapeutic success. The contents of this volume reflect many different aspects of the study of ovulation including the monitoring of both follicular growth and the luteal phase, the role of prolactin and the treatment of ovulatory dysfunction. We are sure that the wide range of topics will evoke continued interest in these subjects. We extend our thanks to the invited speakers for their excellent contributions in lecture and essay form and express our gratitude for the unfailing help we received from the staff of MTP Press in the preparation of this volume.