Social identity and social categorization theories have offered some of the most exciting developments in social psychology - informing work on everything from intergroup relations to personal identity. This comprehensive book surveys the latest empirical and theoretical findings, alongside original contributions, to provide an invaluable overview of this important field. The internationally-renowned contributors explore a broad range of psychosocial phenomena including intergroup discrimination, influence, group polarization, collective behaviour, impact of minorities, prejudice, stereotypes and leadership.