Preterm delivery is probably the most important problem in obstetrics, and a major public health concern. Recent developments - such as the preventive use of progesterone, and new data on possible mechanisms of initiation of parturition - have placed the topic at the forefront of the interests and preoccupation of many in maternal-fetal medicine and obstetrics. Recent studies have found that preterm deliveries have increased even amongst low risk women. Also shown is that assisted conceptions, multiple pregnancies and elective deliveries are associated with early birth. The impact on society is considerable. Preterm birth can also have considerable impact on long-term health, including severe mental or physical disability. With all this being currently debated, Obstetricians should re-evaluate the risks and benefits of delivering babies earlier. This book, published in collaboration with the Society for Gynecologic Investigation, is a balanced, authoritative, well-referenced work with a rigorous underpinning of basic science and evidence-based clinical guidelines. The Editors have ensured that there is development of modern ideas throughout regarding understanding, research, prevention and treatment of preterm birth. The book will be essential reading for Specialists in Maternal-Fetal Medicine, Obstetrics and Perinatology. Since the book also highlights definitions, classifications and management algorithms, it will also be useful to general ObGyns, both in practice and training.