 Friendship, as understood here, is a distinctively personal relationship that is grounded in a concern on the part of each friend for the welfare of the other, for the other’s sake, and that involves some degree of intimacy. As such, friendship is undoubtedly central to our lives, in part because the special concern we have for our friends must have a place within a broader set of concerns, including moral concerns, and in part because our friends can help shape who we are as persons. Given this centrality, important questions arise concerning the justification of friendship and, in this context, whether it is permissible to “trade up” when someone new comes along, as well as concerning the possibility of reconciling the demands of friendship with the demands of morality in cases in which the two seem to conflict.