The diversity of social behavior among birds and primates is surpassed only by members of the Hymenopteran insects, including bees, ants, and the genus Polistes, or paper-wasps. This volume combines incisive reviews and new, unpublished data in studies of paper-wasps, a large and varied group whose life patterns are often studied by biologists interested in social evolution. While this research is significant to the natural history of paper-wasps, it also applies to topics of general interest such as the evolution of cooperation, social parasitism, kin recognition, and the division of labor.