Reinold and Heupel’s introductory chapter articulates the volume’s overarching research question, surveys relevant International Relations and International Law scholarship, proposes a conceptual framework for answering the volume’s question, and presents the structure of the book. The guiding question is whether the coexistence of (partially) overlapping and sometimes competing layers of authority, which characterizes today’s global order, undermines or rather strengthens efforts to promote the rule of law on a global scale. Summarizing the volume’s findings, Reinold and Heupel argue that whether multi-level governance and global legal pluralism have beneficial or detrimental effects on the international rule of law depend on specific scope conditions. Among these are the mobilization of powerful states and courts, and the fit between soft law and hard arrangements.