Chapter 9 The Economics of Human Relationships Behind my reciprocation of a friends gift may lie both instrumental reasons (I expect further future gifts) and communicative reasons (I want to establish or confirm a friendship per se ). In a theory of rational individual action such communicative reasons can be incorporated as an argument of an agents objective function. This chapter starts by reviewing a recent literature that takes this direction and introduces relational concerns through the concept of socially provided goods. From a relational perspective however individual intentions are not all that matters: a relation is characterized by the two (or more) persons linked and by the kind of link they have. This perspective which in our view should complement the more traditional individualistic one is particularly suited to embed individual motivations in their social context and to study their co evolution. In particular we focus on the conditions under which reciprocity and altruism may survive and even spread over as social norms. Drawing from the literature on the dynamics of social norms we argue that the combination of individual incentives and the forces of social selection may lead to a contraposition between a societys material success and its well being i.e. between its vitality and its satisfaction. Finally we consider that the recent literature on the economic analysis of human relationships invites to a new reading of the classics of economics and of moral and political philosophy. Both the new and the old literature point at the need to broaden the scope of economic modeling to lay down the building blocks of a new up to date approach to political economy that is equipped to tackle the challenges posed by advanced industrial societies in their social cultural and economic selection dimensions.