This book discusses altruism as a sociological category similar to the concept of social capital. The author explains why pro-social action is the basis for social capital, and analyzes sociological literature through authors in the field, including Elster, Axelrod, and Williams. Altruism and Social Capital should be read by researchers in sociology as well as students of general sociology and economic sociology. The author simply explains the relationship between altruism and rationality, particularly the kind of rationality produced by game theory. This volume discusses the most recent theories of pro-social action and social capital, and considers their economic consequences.