This introductory chapter sets the conceptual and analytical foundation for the book, which explores the dynamics of socio-environmental conflict and legal mobilisation in Chile. It outlines the research's central aim: to understand how local communities contest extractive projects through law and collective action, and how these struggles are shaped by political, territorial, and historical conditions. Drawing from political ecology, legal mobilisation theory, and social movement studies, the chapter situates Chile as a paradigmatic case of extractivism under neoliberal governance. It introduces the analytical triad used throughout the book—political opportunity structures, framing processes, and resource mobilisation—while also engaging with critiques from the Latin American tradition on territory, resistance, and post-coloniality. The chapter concludes by outlining the book’s structure and methodology, explaining the rationale behind the selection of the three case studies (Alto Maipo, Chiloé, and Caimanes), and previewing the key themes addressed in subsequent chapters. In doing so, it positions the study as both empirically grounded and theoretically innovative, offering insights into the legal, political, and discursive strategies of communities resisting extractive harm.