ENOn 23 September 1939 the world was shocked about signing between the USSR and Germany the Mutual Nonaggression Pact what is often called the Molotov – Ribbentrop Pact. Simultaneously with the pact the Secret Additional Protocol was signed according to which the parties agreed to divide spheres of interests in the Eastern Europe. There is a viewpoint that the USSR had occupied Latvia on the basis of the Molotov – Ribbentrop Pact. On 24 December 1989 the Congress of People’s Deputies of the USSR condemned conclusion of the Secret Additional Protocol with Germany and acknowledged the protocol as null and void since signing. In its turn, on 4 May 1990 the Supreme Council of the USSR acknowledged the Secret Additional Protocol as illegal. What was the influence of the Molotov – Ribbentrop Pact and its Secret Additional Protocol on sovereignty and independence of Latvia? Did the USSR have freedom of actions in Latvia on the basis of the Secret Additional Protocol? How shall the Molotov – Ribbentrop Pact and its Secret Additional Protocol be evaluated from the viewpoint of international law? These and other questions shall not remain without answers. [From the publication]