Introduction: "Through the history of Vietnam's sovereignty over the two archipelagos of Paracel, Spratly, this book provides solid scientific evidence, including historical and legal evidence, asserting long-standing sovereignty of Vietnam for these two archipelagos. The book also presents disputes over the sovereignty of two archipelagoes initiated by China in 1909. Among the Vietnamese studies on Vietnam's sovereignty over the Paracel and Spratly archipelagos, this book is a very elaborate and systematic study. This book contributes to enhancing people's understanding of the history of sovereignty of Vietnam." Materials collected, researched and evaluated include: ancient Han documents in Vietnam, documents of feudal dynasties in Vietnam; Data from archaeological fieldwork including documents, relics and artifacts; Ancient maps of China show that the South China Sea does not quite belong to China; The Western material, in particular, is the material of the East India Company, the Portuguese, the missionaries from Europe, etc. The issues in the book are presented objectively, honestly, properly assess the history and sovereignty of Vietnam