Carl Semb was educated at the University of Oslo, graduating as a Doctor of Medicine. Early in his surgical career he decided to specialize in thoracic surgery, and at the Vardhasen Sanatorium established a celebrated service for the treatment of pulmonary tuberculosis, his outstanding contribution being the operation of extra-fascial apicolysis. Semb was appointed Professor of Surgery at the University of Oslo, and did not confine his interest to any one system in the body. He invited his fellow-countryman Smith-Petersen from the United States to establish a centre for the treatment of painful arthritis, and he gave a Moynihan Lecture at the Royal College of Surgeons on segmental resection of the kidney in the conservative treatment of renal tuberculosis. His clinic in the Ulleval Hospital became a noted training centre for young Norwegian surgeons, and was also a place where all his visitors were given a kindly welcome. His non-professional activities were sailing and skiing, but his courageous support of the resistance movement during the second world war, for which he was awarded the George Cross, will long be remembered with admiration and gratitude. Semb was honoured in many countries. He was made an Honorary Fellow of the American College of Surgeons and of the American Association for Thoracic Surgery. In this country he was an Honorary Member of the Thoracic Society and the Society for Thoracic Surgery, and a corresponding member of the Association of Surgeons. He was admitted to the Honorary Fellowship of the Royal College of Surgeons in June 1960. He died in Oslo in 1972.