The study and practice of organizational psychology is having a growing impact on all our lives and it raises a multitude of fascinating and substantial questions. How does human psychology make organizational behavior possible? How does belonging to organizations affect the way we think, feel and behave? And how is an organization's purpose, performance and culture affected by the individuals and groups within it? Psychology in Organizations addresses these questions by presenting an approach to organizational psychology that draws upon the large body of research that has been informed by social identity and self-categorization theories. In contrast to the individualism that has come to dominate the study of organizations, this approach identifies and explains the distinctive forms of organizational behavior associated with people's membership in-groups and teams. The importance and practical implications of the social identity approach are underlined in a text which provides a review and integrated theoretical treatment of core organization topics - including leadership, motivation, communication, decision-making, negotiation, power, productivity, and industrial protest.