Before World War I I , the great majority of practicing doctors in England and Wales were general practitioners. They had their own surgeries or offices, often in the front room of their own homes, and they were accus­ tomed to dealing with a wide variety of ailments. Some GPs subsequently became specialists, but the majority did not. Specialists were few in number, tended to practice in the large towns, and to be associated with the larger hospitals. In 1939 there was only one specialist to every six or seven GPs, and they were highly concentrated: more than one third of them were in London alone.