This essential legal work by Ibrahim Abbas Al-Jubouri delves into the fundamental principle of diplomatic protection in international law. The study meticulously examines the condition of nationality as the primary link that empowers a state to protect its citizens abroad against violations by other states. It analyzes the legal framework, historical evolution, and contemporary challenges, including dual nationality cases and the protection of corporations. This book is an indispensable resource for students, academics, and practitioners of international law, offering a comprehensive analysis of how nationality serves as the cornerstone for exercising diplomatic protection.