This book is a comprehensive summary of the present state of the art in the physiology of the pregnant uterus and discusses four main themes: First, myometrial physiology and electrophysiology; secondly, hormonal control of labour (including the cervix); thirdly, prostaglandins, infection and immune control of pregnancy; and finally, clinical management of preterm labour treatment and labour induction. It also reviews and discusses the mechanism of action of antiprogestins in the late pregnant uterus and its therapeutic potential in obstetrics. In addition, some basic questions are indicated where further research is needed in both university institutions and the pharmaceutical industry towards understanding the onset of normal and preterm labour. The organisers of the workshop and editors of this volume hope that this book will stimulate basic scientists and clinicians to continue or initiate research on preterm labour.