One of the major advances in cardiology began in the 1930s when André Cournand, a pulmonary physiologist, and Dickinson W. Richards, an expert on cardiovascular medicine, collaborated in a longterm effort to integrate the roles of the heart, the lungs, and the peripheral circulation in gas exchange. Among the initial clinical goals of this research was a clearer understanding of the pathophysiology of pulmonary disease that could answer such questions as the consequences of thoracoplasty and other means then used to collapse the lungs in patients with tuberculosis; it was only later that diagnosis of heart disease emerged as a major practical benefit of this work...