Dryden Phelps Morse, a heart surgeon and pioneer in the development and use of pacemakers, was born in Berkeley, California in 1924. During his childhood, he lived in China for two years with his mother and stepfather. He attended Harvard College from 1941 to 1943 and then entered military service in World War II. He received his M.D. from Columbia University College of Physicians and Surgeons in 1947. Morse did most of his residency training in Philadelphia. His thoracic surgery residency was at Hahnemann Hospital and at the Bailey Thoracic Clinic under pioneer heart surgeon Charles P. Bailey. Morse served in the American Medical Corps in the Korean War, 1952-1954. From 1962 to 1972 he was Chairman of the Department of Thoracic and Cardiovascular Surgery at Albert Einstein Medical Center, Northern Division, in Philadelphia. From 1961 to his retirement in 1991 he was associated with Deborah Hospital in Browns Mills, N.J., as an attending physician. From 1979 on, he served as Director of the Pacemaker Clinic, and full-time attending surgeon, Thoracic Surgical Service, at Deborah. Morse published extensively including a book on heart surgery (1963) and three editions of a guide to pacemakers. He was an expert on the technology of pacemakers and invented several improvements such as the Morse-Edwards Horseshoe annuloplasty ring, and a telephone pacer monitoring system with Ted Stern. Morse was a founding member of the North American Society for Pacing and Electrophysiology in 1979, now the Heart Rhythm Society. At least twice he was invited to lecture in China.