A Power of Attorney (POA) is a legally binding instrument wherein a competent adult, known as the principal, grants authority to another individual, the agent or attorney-in-fact, to act on their behalf in specified legal or financial matters. This delegation of authority must be documented in writing and typically requires either notarization or the signatures of two witnesses to be legally valid, depending on the jurisdiction and the specific powers being granted. The legal definition emphasizes that the agent acts in a fiduciary capacity, meaning they are bound to act in the principal's best interests and according to the terms outlined in the POA document. Furthermore, the scope of authority can be broad, encompassing a wide range of actions, or limited to specific transactions or time periods, and the POA may be durable, remaining effective even if the principal becomes incapacitated.