English Summary/英文概要： Convention on the definition of aggression signed on 3 July 1933, established the borders of modern Romania. As in the case of its neighbors, Czechoslovakia and Poland, revisionist currents in Europe during the interwar period threatened Romania’ s newly established frontiers, one of the most serious threats being posed by the Soviet Union which sought to regain possession of Bessarabia, a Romanian territory that had been occupied by Russia from 1812-1918. This book is a comprehensive account of the efforts of Romanian diplomacy during the interwar period to protect Bessarabia from the Soviet threat and the diplomatic and military events that led to the forcible occupation of the Romanian territories of Bessarabia and Northern Bucovina by the Soviet Union in the summer of 1940. The author not only provides an important account of Romanian diplomacy during this period, but also sheds light on the foreign policies of the Western powers, the Soviet Union, and Nazi Germany in this area of Europe. It is a key work on Romanian foreign policy during the interwar period and a necessary addition to any research library.