A power of attorney allows you to select an individual to make decisions for you if you are unable.  A power of attorney can be quite broad (giving a lot of power to make decisions) or narrow (perhaps only allowing one type of decision—such as the ability to sign a particular contract).  Historically, a power of attorney ceased to be effective when the principal (the person giving the power of attorney) died or became incapacitated.  A “durable” power of attorney continues to be effective upon incapacity.  It is a useful—but potentially quite dangerous—tool.