Sir William Osler, 1st Baronet, FRS, FRCP (July 12, 1849 – December 29, 1919) was a Canadian physician and one of the four founding professors of Johns Hopkins Hospital. Osler created the first residency program for specialty training of physicians, and he was the first to bring medical students out of the lecture hall for training.

Following post-graduate training in Europe, Osler returned to the McGill University Faculty of Medicine as a professor in 1874. Here he created the first formal journal club. In 1884, he was appointed Chair of Clinical Medicine at the University of Pennsylvania in Philadelphia and in 1885, was one of the seven founding members of the Association of American Physicians, a society dedicated to “the advancement of scientific and practical medicine.” When he left Philadelphia in 1889, his farewell address. “Aequanimitas”, was on the equanimity necessary for physicians.

Perhaps Osler’s greatest influence on medicine was to insist that students learn from seeing and talking to patients and the establishment of the medical residency.

In 1889, he accepted the position as the first Physician-in-Chief of the new Johns Hopkins Hospital in Baltimore, Maryland. Shortly afterwards, in 1893, Osler was instrumental in the creation of the Johns Hopkins School of Medicine and became one of the school’s first professors of medicine. Osler quickly increased his reputation as a clinician, humanitarian, and teacher. He presided over a rapidly expanding domain. In the hospital’s first year of operation, when it had 220 beds, 788 patients were seen for a total of over 15,000 days of treatment. Sixteen years later, when Osler left for Oxford, over 4,200 patients were seen for a total of nearly 110,000 days of treatment.

In 1905, he was appointed to the Regius Chair of Medicine at Oxford, which he held until his death. He was also a Fellow of Christ Church, Oxford. In 1911, he initiated the Postgraduate Medical Association, of which he was the first President. In the same year, Osler was named a baronet in the Coronation Honours List for his contributions to the field of medicine. The largest collection of Osler’s letters and papers is at the Osler Library of McGill University in Montreal and a collection of his papers is also held at the United States National Library of Medicine in Bethesda, Maryland.