IN CHRONIC empyema the deposition of fibrous tissue on the pleural surfaces results in an immobile, unyielding and nonexpansile lung. This problem has confronted and baffled physicians since the time of Hippocrates. It was not until the nineteenth century, with the introduction of anesthesia, antisepsis, and later roentgen ray, that any definite effort was made to cope with this debilitating condition. Letievant,1 in 1860, and later Simon, in 1869, suggested multiple rib resection. It remained for Estlander2 in 1879 to popularize this procedure. They rationalized that if a lung failed to meet the chest wall, then the chest wall must be collapsed to meet the lung. Schede3 pointed out in 1890 that not infrequently the thick, stiff pleura did not permit the chest wall to collapse following thoracoplasty. He overcame this obstacle by removing the parietal pleura, intercostal bundles, and ribs overlying the empyema space—so-called cavity unroofing.