Research on the Vietnam - American War is generally not new. But the novelty of this work is the approach to study the issues & problems from the perspective of international relations, especially the “triple” relationship between Vietnam - the Soviet Union - China. Inheriting the research results of the predecessors, plus both rich and diverse sources at home and abroad, the author analyzes the movement of the triangular relationship between Vietnam and the two largest socialist powers - the Soviet Union and China - between 1954 and 1975. The book consists of 3 major sections (8 chapters). In Part 1, the author presents the theoretical basis of the strategic triangulation, its formation, characteristics and implications for the case of Vietnam. In Part 2, the author analyzes the basis of the formation of the Vietnam - Soviet Union - China relationship, the process of mobilization as well as the outcome of these relations through the stages of the war. In Part 3, the author assesses in a comprehensive way the effects of Vietnam - the Soviet Union – China triangular relationship on the situation of war, with each country, region and the world.