Advance directives are legally recognized documents that allow competent adults to communicate their healthcare preferences in advance, ensuring their wishes are respected if they become unable to make or communicate decisions due to illness, injury, or cognitive decline. The legal and ethical foundation of advance directives rests on four core bioethical principles: autonomy (the right of individuals to make informed decisions about their own healthcare), beneficence (acting in the patient's best interest), non-maleficence (avoiding harm), and justice (fair and equitable allocation of healthcare resources). Patient autonomy is the primary ethical principle underlying advance directives, recognizing that every competent adult has the fundamental right to accept or refuse any medical treatment, including life-sustaining interventions. There are two primary types of advance directives. A living will is a written document in which an individual specifies the types of medical treatments they do or do not want if they become terminally ill or permanently unconscious and are unable to communicate. A living will may address preferences regarding mechanical ventilation, cardiopulmonary resuscitation, tube feeding, dialysis, blood transfusions, and organ donation. A durable power of...