Chapter 2 lays the foundation for the book’s theoretical framework by introducing the collective action problem and examining how protest mobilization unfolds in practice. Drawing on global literature and empirical examples, it demonstrates that elite-driven protest is a widespread and influential form of collective action. It shows, however, that successful elite mobilization requires deep local knowledge, strong community networks, and trust – resources that many elites lack. To overcome this gap, the chapter introduces the concept of the protest broker: an intermediary who facilitates connections between elites and potential protesters. It explores who protest brokers are, what they do, and why their role is central to protest mobilization. It argues further, that existing theories of elite mobilization implicitly assume the presence of such intermediaries, yet rarely acknowledge them explicitly. By making protest brokers visible, this chapter reframes key assumptions in the protest literature and connects them to broader research on political and vote brokers. It also situates protest brokers among other grassroots actors – such as shop floor stewards and activists – clarifying their unique but overlapping functions in enabling protest and shaping its location and form.