Death used to be a simple affair: either a person’s heart was beating, or it was not. That clarity faded years ago when heroic medical technology started to keep hearts beating indefinitely. Although we have had decades to ponder the distinctions between various states of grave physiological failure, if anything our confusion has grown. When is it ethical to turn off a ventilator or remove a feeding tube? When does “life support” lose its meaning? And most critically, at what point is it acceptable to cut into a body and remove the heart that could save another life?