Preterm delivery is 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. This balanced, authoritative, and well-referenced work offers a rigorous underpinning of basic science, highlighted translational science sections, and evidence-based clinical guidelines.