It has been an honor to be the editor of the second edition-first major revision in 30 years-of Netter's Respiratory System. The changes that have occurred over the past 3 decades in pulmonary medicine have been profound. The challenge of editing this edition has therefore been to include these updates while at the same time preserving the unique nature and artistic beauty of Netter's classic depiction of human health and disease. In addition to ensuring the accuracy and relevance of the timeless topics of anatomy and physiology， we have significantly revised the sections on airways， parenchymal and pleural diseases， lung cancer， infectious diseases， thromboembolic disease， inhalational diseases， acute respiratory distress syndrome， pharmacotherapy， radiology， mechanical ventilation， and trauma and surgery. New sections have been created on pulmonary immunology， pulmonary hypertension， lung manifestations of systemic disease， sleep medicine， exhaled breath analysis， endobronchial ultra-sound， video-assisted thoracoscopic ultrasound， lung volume reduction surgery， and lung transplantation. I am indebted to the many outstanding contributors to this edition， who are each international experts in their field. Without their input， it would have been impossible to ensure that the most up-to-date， accurate information would be provided to bring Netter's Respiratory Disease into the 21st century. I would like to thank especially those contributors who have been my teachers and mentors over the years： Drs. David Badesch， Jason Bates， Gerry Davis， Barry Make， Ted Marcy， Polly Parsons， Charlie Irvin， Richard Irwin， Mike Iseman， and Talmadge King. Special thanks also go to Dr. Jeffrey Klein， who made extra efforts to provide radiographic images for many different sections of the book. Finally， I want to dedicate this work to my grandfather， Dr. Edward Budnitz， who shared with me his love of medicine and inspired me to pursue a career as a physician.