Enormous gains have been made in me pathophysiologic understanding and therapy of pulmonary hypertension, particularly over the past decade. Pulmonary Hypertension aims to provide a current, comprehensive, and clinically relevant perspective on these gains, with contributions from accomplished experts. As background. Alfred P. Fishman. MD. a leader in the field for more than four decades, offers his unique perspective on developments in the field over the past century, including the development of right heart catheterization techniques by individuals with whom he subsequently worked, the first descriptions of ''primary'' pulmonary hypertension, the formation of the NIH registry, and earlier attempts to classify the disease.The subsequent text provides an overview of the current stale of the art. Descriptions of the present iteration of the classification system (as refined by the World Health Organization [WHO] consensus conference in 2003) and diagnostic approach occupy the next two chapters, followed by insights into pathophysiology, genetics, and the role of the right ventricle. These provide the foundation for Chapters 6-10, which discuss specific conditions associated with pulmonary hypertension, including those from WHO Groups I, 2, 4, and 5. Chapter 10 is authored by experts from the center (University of California, San Diego) with the greatest experience in surgical management of the disease.