International law shapes nearly every aspect of our lives. Yet it is often considered the exclusive domain of professionals with years of legal training. This second edition text uses clear, accessible writing and contemporary examples to explain where international law comes from, how actors decide whether to follow it, and how it is upheld using legal and political tools. Suitable for undergraduate and graduate students, this book is accessible to a wide audience and is written for anyone who wants to understand how global rules shape and transform international politics. Each chapter is framed by a case study that examines a current political issue, such as Russia's invasion of Ukraine, or the Israel/Gaza war, encouraging students to draw connections between theoretical concepts and real-world situations. The chapters are modular and are paired with multiple Supplemental Cases: edited and annotated judicial opinions. Accompanied by ready-to-use PowerPoint slides and a test bank for instructors.