Bound by a common profession and motivation to heal, physicians still can be moral strangers. Some physicians exercise claims of conscience to avoid participating in interventions such as abortion and physician-assisted suicide that violate their deeply held values or religious beliefs. Disagreements about these interventions transcend beliefs and values; they embody different conceptions of the goals of medicine and the meaning of conscience itself. This month’s authors seek to understand claims of conscience more fully and find ways for physicians to act in good conscience without alienating or abandoning those who seek care.