This volume examines the building blocks of environmental law across different jurisdictions. More specifically, it provides a cartography of environmental law, with a focus on its underlying logic, main arrangements and their variations, and how it is embedded within the broader legal arrangements developed to tackle other questions. In this context, this preliminary chapter provides an overview of the comparative method as it applies to the overall research project leading to the present volume. It discusses descriptive and evolutionary approaches, the conceptual approach, the functionalist approach, the factual approach, legal formants, the contextualist approach, and legal transplants. It then considers a range of methodologies proposed by comparative law experts, including the bottom-up functionalism and top-down functionalism, before explaining the methodology used for the organization of this book. The chapter concludes by summarizing a tentative structure of comparative environmental law as a single overall technology.