Most people believe that there are limits to the sacrifices that morality can demand. Although it would often be meritorious, we are not, in fact, morally required to do all that we can to promote overall good. What's more, most people also believe that certain types of acts are simply forbidden, morally off limits, even when necessary for promoting the overall good. In this provocative analysis Kagan maintains that despite the intuitive appeal of these views, they cannot be adequately defended. In criticizing arguments for limited moral requirements as well as those for unconditionally prohibited acts, Kagan offers a sustained attack on two of the most basic features of ordinary common sense morality.