Since boyhood days in Toronto, I have trailed the legend of William Osler. In 1908, I followed his path to Baltimore and The Johns Hopkins Medical School. As an undergraduate at Hopkins, I heard Osler deliver his famous address on the discovery of the pulmonary circulation by Servetus. Again in 1916, then an army medical officer, I took to the Osler trail and followed it to Britain and the British Expeditionary Force in France. In the succeeding years of the First World War, I learned much concerning William Osler. Among my informants were a number of Osler's associates from Oxford, who were impressed by the important influence he was exerting in academic circles and, particularly, in medicine at Oxford and in Great Britain. With this introductory background and the passing of a generation since the death of Osler in 1919, it seems appropriate to attempt a fresh assessment of his