Birth is a sudden, traumatic transition of environments. Once the placental oxygen supply ceases, the foetus has only minutes to establish pulmonary oxygen transport, which requires not only inflation of the lungs, but also sudden and sustained changes in the lung circulation. Not long ago, research in this field was largely restricted to morphology and physiology. Now the powerful new tools of cellular and molecular biology have begun to shed light on the physiological processes in the developing lung and its supporting vasculature. In 22 chapters, three main sections explore lung growth and development, vascular cell growth and differentiation, and the mechanisms of hemodynamic control in the neonate; extensive illustrations give a comprehensive picture of pulmonary circulatory development. Factors controlling vasculogenesis and angiogenesis are described by the scientists who pioneered the field. Similarly, the intracellular signaling cascades that determine proliferation or growth inhibition of fibroblasts, smooth muscle cells, and endothelial cells are also presented in an understandable manner. Finally, the role of substances, such as nitric oxide and endothelin, that control the hemodynamics of the fetal and neonatal circulations are discussed in detail, particularly in relation to the changes occurring at birth. This book will inform basic scientists as well as the clinician and student, and should be of particular interest to pediatric cardiologists, pulmonary medicine physicians, and vascular biologists.