This book represents a comprehensive update on pulmonary surfactant by merging classical knowledge with new information. Topics include surfactant secretion and alveolar processing and recycling; physical bases and different theoretical models of the physiological mechanism for pulmonary surfactant action; recent findings on surfactant-like material in other organs; developmental processes and multifactorial regulation; etiology and physiopathology of neonatal respiratory distress; and modern methods for functional explorations of the lung in neonates and experimental models in animals. The book also contains a discussion on the management of hyaline membrane disease, from both the experimental and clinical points of view.