A social dilemma is a situation in which the interests of the collective and its individual members clash. In these situations individuals typically are tempted to take actions that favor (sometimes even maximize) their short-term egocentric interests. However if all group members adopt such behaviors, the group suffers since all its members are worse off than they could be by endorsing alternative pro-social actions that favor (sometimes even maximize) the collective interest. This 2004 book provides an overview and summary of the state of social psychological research on social dilemmas. It is organized around four core issues: individual differences which determine people's preferences for outcomes that promote either their own or their group's well-being; the study of dynamic processes based on simulations of artificial societies; social dilemmas that emerge in inter-group conflicts; and the effect of various types and sources of uncertainty on behavior in social dilemma situations.