Aarti Iyer received her PhD in Social Psychology from the University of Santa Cruz (2004), and she is currently a faculty member at the University of Queensland (Australia). Martijn van Zomeren received his PhD from the University of Amsterdam (2006), and he is currently a faculty member at the University of Groningen (The Netherlands).Both editors' research interests involve collective action, social change, emotion, and identity processes.

• INTRODUCTION.Introduction to the Social and Psychological Dynamics of Collective Action (Martijn van Zomeren and Aarti Iyer).  COLLECTIVE ACTION BY LOW-STATUS GROUPS.Metaphors of Protest: A Classification of Motivations for Collective Action (Martijn van Zomeren and Russell Spears).Pathways to Collective Protest: Calculation, Identification, or Emotion? A Critical Analysis of the Role of Group-Based Anger in Social Movement Participation  (Stefan St¨urmer and Bernd Simon).Collective Psychological Empowerment as a Model of Social Change:Researching Crowds and Power (John Drury and Steve Reicher).Collective Action-and Then What? (Winnifred R. Louis).Collective Action in Modern Times: How Modern Expressions of Prejudice Prevent Collective Action  (Naomi Ellemers and Manuela Barreto).COLLECTIVE ACTION BY HIGH-STATUS GROUPS.Why Do the Privileged Resort to Oppression? A Look at Some Intragroup Factors  (Tom Postmes and Laura G. E. Smith).Why Do Men and Women Challenge Gender Discrimination in the Workplace? The Role of Group Status and In-group Identification in Predicting Pathways to Collective Action (Aarti Iyer and Michelle K. Ryan).BEYOND STATUS: COLLECTIVE ACTION AROUND OPINIONS AND POLICY OPPOSITION.Context Matters: Explaining How and Why Mobilizing Context Influences Motivational Dynamics(Jacquelien van Stekelenburg, Bert Klandermans, and Wilco W. van Dijk).Collective Action as the Material Expression of Opinion-Based Group Membership (Craig McGarty, Ana-Maria Bliuc, Emma F. Thomas,and Renata Bongiorno).COMMENTARY.The Next Generation of Collective Action Research (Stephen C. Wright).