Daniel Callahan - whose cofounding of The Hastings Center in 1969 was one of the most important milestones in the history of bioethics - has written on an uncommonly wide range of issues over a long career. They have moved back and forth between clinical care of individual patients and theethical problems of health care research and delivery. Through his many writings, four core problems have recurred in all of his work, and influence each of the others. What is health and how has its understanding been shaped by medical progress and the culture of medicine and society? What is progress, a deep value in modern health care and how should we judge it? What kinds of technological innovations that come out of the drive for progress are really good forus - and what do we do when there is a clash between individual good and social good in the use of expensive technologies, a problem now evident in the unsustainable high costs of health care? How should our understanding of the place of an inevitable death in all our lives, and its place inmedicine, help us to better think of the goals of medicine and the goals of our life in seeking a good death? Those four questions have been with bioethics from its beginning and will remain with it for the indefinite future. They are the roots of bioethics.