RESUMO
William Osler was the greatest physician of his time. Specialists reading his textbooks agreed that in their own specialities he was accurate and illuminating. His grasp of dermatology was particularly striking and skin changes are prominent in five of the syndromes named after him and in at least 100 of his papers. This paper describes how his early training in dermatology under Tilbury Fox in London and Hebra in Vienna combined with his unusual personal qualities to enable him to make massive contributions to a wide variety of dermatological topics. These include smallpox, cutaneous tuberculosis, nail growth, leprosy, scleroderma, pigmentation and purpuric eruptions as well as the more obvious hereditary haemorrhagic telangiectasia, angio-neurotic oedema and Osler's nodes.