Recipient of the 2025 Social Sciences Book Award of the International Academy of Astronautics! The Japanese version of this text received the Riese Award from the Air Law Institute of Japan. What kind of document should be created to solve the problem of space activities? This book uses case studies to illustrate how normative approaches in space law differ from those in other fields, delving into the history of norms and treaties in space law, contemporary issues concerning space activities, and issues surrounding debris removal and mitigation. Its analytical approach will be useful for readers who study how the basic theory of public international law can apply to new frontiers in space law.