John Collins Warren (1778-1856) represented the apex of surgery and medicine of the first half of nineteenth century Boston. Educated at Harvard College where he obtained a Bachelor of Arts in 1797, he contemplated the idea of a business career prior to setting sail for a traditional medical education at Europe's finest universities. From 1799 to 1802, he attended prestigious medical and surgical lectures in London, Edinburgh, and Paris. Warren received an honorary MD from Scotland's St. Andrews University in 1802. He then returned to Boston and joined his father's practice. In 1815, he followed his accomplished father as the Hersey Professor of Anatomy and Surgery at Harvard Medical School. He held this position with great distinction until 1847 when he retired as professor emeritus. From 1816 to 1819 he served as Harvard Medical School dean and received an honorary medical degree at the end of his term.John Collins Warren had numerous surgical accomplishments during his illustrious career. Clinically, he was active and varied in his practice, operating on strangulated hernias, tumors, and cataracts, in addition to performing vascular surgery and amputations. He published many articles and books of widespread circulation. Professor Warren also performed the first reported case of ether anesthesia administered by William T. Morton on October 16, 1846. Outside the operating theatre, Doctor Warren and his colleagues were revered for founding the Massachusetts General Hospital in 1821, and years before, in 1812, Warren and his associates established the New England Journal of Medicine and Surgery. In light of his varied contributions, John Collins Warren is remembered as a dedicated and innovative surgeon, as well as a committed medical educator, able administrator and effective leader.