Perhaps the defining feature of humanity is the social condition -- how we think about others, identify ourselves with others, and interact with groups of others. The advances of evolutionary theory, social cognition, social identity, and intergroup relations, respectively, as major fields of inquiry have been among the crowning theoretical developments in social psychology over the past three decades. Marilynn Brewer has been a leading intellectual figure in the advancement of each of them. Her theory and research have had international impact on the way we think about the self and its relation to others. This festschrift celebrates Marilynn's numerous contributions to social psychology, and includes original contributions from both leading and rising social psychologists from around the world. The volume will be of interest to social psychologists, industrial/organizational psychologists, clinical psychologists, and sociologists.