Let us suppose that organ transplant procedures have been perfected; in such circumstances if two dying patients could be saved by organ transplants then, if surgeons have the requisite organs in stock and no other needy patients, but nevertheless allow their patients to die, we would be inclined to say, and be justified in saying, that the patients died because the doctors refused to save them. But if there are no spare organs in stock and none otherwise available, the doctors have no choice, they cannot save their patients and so must let them die. In this case we would be disinclined to say that the doctors are in any sense the cause of their patients' deaths. But let us further suppose that the two dying patients, Y and Z, are not happy about being left to die. They might argue that it is not strictly true that there are no organs which could be used to save them. Y needs a new heart and Z new lungs. They point out that if just one healthy person were to be killed his organs could be removed and both of them be saved. We and the doctors would probably be alike in thinking that such a step, while technically possible, would be out of the question. We would not say that the doctors were killing their patients if they refused to prey upon the healthy to save the sick. And because this sort of surgical Robin Hoodery is out of the question we can tell Y and Z that they cannot be saved, and that when they die they will have died of natural causes and not of the neglect of their doctors. Y and Z do not however agree, they insist that if the doctors fail to kill a healthy man and use his organs to save them, then the doctors will be responsible for their deaths. Many philosophers have for various reasons believed that we must not kill even if by doing so we could save life. They believe that there is a moral difference between killing and letting die. On this view, to kill A so that Y and Z might live is ruled out because we have a strict obligation not to kill but a duty of some lesser kind to save life. A. H. Clough's dictum 'Thou shalt not kill but need'st not strive officiously to keep alive' expresses bluntly this point of view. The dying Y and Z may be excused for not being much impressed by Clough's dictum. They agree that it is wrong to kill the innocent and are prepared to agree to an absolute prohibition against so doing. They do not agree, however, that A is more innocent than they are. Y and Z might go on to point out that the currently acknowledged right of the innocent not to be killed, even where their deaths might give life to others, is just a decision to prefer the lives of the fortunate to those of the unfortunate. A is innocent in the sense that he has done nothing to deserve death, but Y and Z are also innocent in this sense. Why should they be the