Why do people protest? And how can people protest effectively? This book is about the psychological science and practical art of social protest, based in the psychology of motivation and mobilization. Based on decades of theorizing and research, the book offers a summary of knowledge about core motivations for social protest, a tactical triad regarding the effectiveness of social protest, and relational tools toward mobilization. Furthermore, Social Protest integrates those insights into a new relational-psychological theory of social protest with a motivational and strategic pillar - a theory that turns knowledge into understanding by portraying protesters as relational actors. Van Zomeren further offers a guide toward the contextualized application of the theory's motivational and strategic pillars to real-life social protests, including a concrete checklist for practitioners who seek to motivate people to mobilize on the basis of the core motivations, the tactical triad, and relational mobilization tools. Finally, the book offers an outline of the bright horizons that researchers need to work toward if they want to enable their theories to make more specific and useful recommendations for the practical art of social protest, and hence to effectively use social protest as a powerful pathway to positive social change.