This is a handbook of ethics for a diverse audience of health care providers. Its subject is the moral and legal force of 'advance directives', which are documents intended to declare and preserve the values, choices, and preferences of patients in the event that they become unable to make decisions about their own health care. The posture of the work is one of strong support for patients' individual health care choices, and encouragement of thoughtful use of advance directives to that end. The work presents a historical and conceptual examination of the patient's role in medical decision making and the refusal of treatment, with special attention to the problems of advance decision making. It examines the types and models of advance directives currently in common use and gives suggestions both about helping patients to write directives and about interpreting and making use of directives prepared by patients and encountered by clinicians. Finally, the implications of the suggested policy are examined in light of growing concerns about the scarcity of funds and resources for health care.