Chapter 2 inquires why cooperation takes place and why it emerges between formally distinct actors. The main claim made in this Chapter is that organizations cooperate because in the fragmented, pluralistic context they each hold incomplete authority. Cooperation becomes necessary for regulators to gain the authority to effectively regulate. In addition to giving a general account of authority in the transnational context, Chapter 2 looks in particular at the various regulatory competences that actors exchange in the course of the cooperative processes. This is termed ‘regulatory resources exchange’. Chapter 2 also focuses on how various understandings of legitimacy affect the relationships between different types of actors and their targeted communities. It is argued that, in particular, origin- and tradition-based rationales and considerations play an important role in the determination of the legitimacy of transnational actors and their regulation. Chapter 2 also examines the rise of epistemic authority and how the increase in expertise-driven governance transforms private actors into important partners in regulatory processes.