This book is an inquiry into identity in modern society. The inquiry starts from the social psychological premise that identity both results from interaction in the social world and in turn guides interaction in the social world. It builds on and incorporates insights from philosophy, cognitive neuroscience, psychology, cultural studies, anthropology and sociology. The theoretical heart of the book is an integrative social psychological approach which revolves around the author's self-aspect model of identity (SAMI). The text reviews previous research guided by SAMI, but also further refines the model. In addition, it places particular emphasis on identity in the context of minority-majority relations, intercultural contact and conflict, and participation in collective action. The book concludes by identifying areas of identity worthy of future research.