This study describes the evolution of the Nazi-Soviet relations between 1939 and 1941. It shows how, following the Munich fiasco of the Western diplomacy, the commercial and economic ties between Germany and the U.S.S.R. have improved at first, followed by the establishment of a strong political understanding of the mutual benefits resultant of this relationship; this ascendant evolution will lead inevitably to the infamous Molotov-Ribentrop agreement. The second part of this study refers to the subsequent Nazi-Soviet efforts of establishing the Soviet Union as a member of the Rome-Berlin-Tokyo Axis directed against Britain and the U.S., efforts in which both sides showed great interests and that reached climax during October-November 1940. In the last part we show why and how these efforts had failed, generating the circumstances which led to the Nazi invasion of Soviet Union in June 1941