This book examines the evolving landscape of payment and settlement systems amid rapid technological advancements and new market entrants, emphasising the critical role of robust legal frameworks in fostering stability, efficiency, and financial inclusion. The concept of secure, efficient, and accessible payment and settlement systems supported by robust legal frameworks and processes as the foundation of a stable financial system is not new. However, rapid technological developments and the entrance of new players have transformed, perhaps even disrupted, the payment ecosystem. This book explores the design, oversight, and enforcement of regulatory environments, offering a critical analysis of current policy and legislative initiatives to address risks and enhance system resilience. Integrating insights from regulatory theory, corporate governance, economics, and central banking, the book navigates tensions between public and private oversight, innovation, and legal clarity, particularly in costly cross-border payments. It debates whether regulators should merely mitigate risks or actively reshape financial infrastructures to harness the transformative potential of payment systems for global economic and societal benefit. This book will be of interest to researchers in the law of emerging technologies, financial and banking law and economics.