Introduction -- Part I. Theory: 1. Competence and incompetence -- 2. The primary ethical framework: patient-centered principles -- 3. Advance directives, personhood, and personal identity -- 4. Distributive justice and the incompetent -- Part II. Application: 5. Minors -- 6. The elderly -- 7. The mentally ill -- Looking forward -- Appendix 1: living trust and nomination of conservatorship -- Appendix 2: durable power of attorney for health care