Epistocracy is on the rise. The chapters in this volume all document, in one way or another, the role of experts and knowledge organizations in the development of global policies and their implementation by international organizations, donor agencies, and other globally mobile policy actors. The constellations of these actors are called here ‘transnational policy commu¬nities’. They form around a specific policy problem (like refugees or ocean pollution) or alternatively around a policy sector (like global health policy or global environmental policy). Other terms have been used in this volume. Eve Fouilleux writes about the concept of a transnational ‘organizational/institu¬tional field’ that is composed of both a set of institutions, including practices, understandings, and rules as well as a network of organizations. It matters less the terminology used, and the disciplinary or conceptual frame adopted, as all the chapters point to new spaces for making global policy not only inside inter¬national organizations but also in their interactions. These transnational policy communities help fill the void of authority at the global and regional levels where there are ‘non jurisdictional spaces’ such as the oceans, the Antarctic, or global care chains.