Social Groups in Action and Interaction reviews and analyzes the human group as it operates to create both social good and, potentially, social harm. It summarizes current knowledge and contemporary research, with real-world examples in succinct yet engaging chapters, to help students understand and predict group behavior. Unlike other texts, the book considers a wide range of topics-such as conformity, leadership, task performance, social identity, prejudice, and discrimination-from both an intragroup and an intergroup perspective. By looking at behavior both within and between groups, it bridges the gap between these interconnected approaches. The second edition is thoroughly updated to include new discussion of the biology and neuroscience of group formation, recent developments in social identity theory, and recent advances in the study of social networks. It also includes questions for review and discussion in the classroom. It provides the most comprehensive and essential resource for courses on group dynamics and behavior.