Daniel Callahan helped invent the field of bioethics more than forty years ago when he decided to use his training in philosophy to grapple with ethical problems in biology and medicine. Disenchanted with academic philosophy because of its analytical bent and distance from the concerns of real life, Callahan found the ethical issues raised by the rapid medical advances of the 1960s--which included the birth control pill, heart transplants, and new capacities to keep very sick people alive--to be philosophical questions with immediate real-world relevance. In this memoir, Callahan describes his part in the founding of bioethics and traces his thinking on critical issues including embryonic stem cell research, market-driven health care, and medical rationing. He identifies the major challenges facing bioethics today and ruminates on its future. Callahan writes about founding the Hastings Center--the first bioethics research institution--with the author and psychiatrist Willard Gaylin in 1969, and recounts the challenges of running a think tank while keeping up a prolific flow of influential books and articles. Editor of the famous liberal Catholic magazine Commonweal in the 1960s, Callahan describes his now-secular approach to issues of illness and mortality. He questions the idea of endless medical "progress" and interventionist end-of-life care that seems to blur the boundary between living and dying. It is the role of bioethics, he argues, to be a loyal dissenter in the onward march of medical progress. The most important challenge for bioethics now is to help rethink the very goals of medicine.