Throughout recorded history, a series of seemingly unrelated ideas have been consistently intertwined: suicide, euthanasia, infanticide, eugenics, genocide and, most recently, the practice termed physician-assisted suicide. From Plato and Hippocrates to a pair of twentieth-century American physicians named Haiselden and Kevorkian, an examination of history shows these disparate notions always involve two troublesome questions: Which lives are not worth living? And who will decide? The same examination of history teaches that separating the worthy from the not worthy is a very dangerous proposition, especially for those whose lives are deemed marginal.