There are numerous conflicts around the world concerning the ownership of territories, annexations, and secessions. Discussions between the parties involved often bring up emotionally charged historical events that are intended to prove or disprove claims. This book shows that this type of argumentation is futile and does not provide a suitable basis for resolving such conflicts. Starting with a definition of the terms “people,” “nation,” and “state,” the book describes and develops the legal and philosophical foundations that can be used to objectively assess and resolve territorial conflicts. These rules are then applied to specific examples, ranging from South Tyrol to Palestine, Catalonia, Kosovo, California, Eastern Ukraine, Kashmir, and East Timor. The book is aimed not only at academics but also at citizens with an interest in history and politics who want to better understand territorial conflicts and form their own informed opinion on how they may be resolved.