'Ethnic cleansing', 'institutional racism', and 'social exclusion' are just some of the terms used to describe one of the most pressing social issues facing today's societies: prejudice and intergroup discrimination. Invariably, these pervasive social problems can be traced back to differences in religion, ethnicity, or countless other bases of group membership: the social categories to which people belong. Social categorization, how we classify ourselves and others, exerts a profound influence on our thoughts, beliefs, feelings, and behaviors. In this volume, Richard Crisp and Miles Hewstone...