This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book discusses the work of twelve social justice organizations that orient to youth crime as a product of social injustice, their creative ideas about how working to bring about social change can foster personal change. Drawing on qualitative interviews with organizational staff, this book explores how the work of these grassroots groups relates to criminology and the governance of crime in the neoliberal moment. Some organizations focused their efforts on working with younger youth "at-risk" of crime, while others worked with older youth with significant histories in the juvenile or criminal justice system. Activist-oriented social justice organizations organized popular protest and advanced advocacy efforts towards criminal justice and social reform. Throughout history, community-based grassroots efforts have fought for social change in the US and around the world.