This chapter synthesises the key themes of the book, focusing on how the new psychology of intergroup relations advances our understanding of social change. The chapter first summarises how the new approach enhances traditional theories and methods, highlighting the role of place, time and change in group processes and intergroup relations. Multi-group dynamics create a complex system which is marked by intersectionality, and the interplay of stability, conflict and innovation. Further, the chapter explores how individuals and groups can engage with the new psychology of system change. It stresses the importance of altering relationships, understanding pushback and articulating shared visions to address collective threats with effective solutions. The need for enhanced perception of latent forces in social and physical environments is emphasised, alongside the call for connecting knowledge and power across mainstream institutions. The chapter considers how readers can be equipped to understand and effect change locally and globally, and to see and intervene in the broader socio-ecological system.