This combined textbook of obstetrics and gynaecology aims to present the essential information required by medical students in their clinical course. Eight weeks is the usual allocation for undergraduate clinical training in obstetrics and gynaecology. Therefore, this textbook has been written to provide the core of knowledge which medical students need to supplement their clinical experience and help them to master the essentials of obstetrics and gynaecology in that short 8-week period. It has been planned to bridge the gap between the vast postgraduate tomes and the very brief lists of facts in the "pocket" books, providing students with one combined course book. The author has tried to focus throughout on the common conditions encountered in clinical practice. Particular emphasis has been placed on certain chapters that form the physiological basis of obstetrical and gynaecological practice. For example, the chapters on physiological changes in pregnancy and on conception and nidation are essential platforms on which to build a knowledge of abnormal states of fertility and reproduction and therefore receive greater emphasis than many other sections. Some of the sections such as those related to the mechanisms of normal and abnormal labour remain essentially unchanged.