For the first time, documents from the Special Archive of Lithuania, published in this edition, give the reader a unique opportunity to look “behind the scenes” of Lithuanian foreign policy in 1939–1940, to learn about the secret pro-German plans of Lithuanian President A. Smetona, about informal soundings of the possibility of establishing a German protectorate over Lithuania, about the secret cooperation of Lithuanian and Nazi intelligence services in the fight against the Polish resistance movement. These materials contain unique assessments of Soviet-German relations in 1939–1940, given by Nazi intelligence officers and Lithuanian politicians, and also allow us to take a fresh look at the motivation for the actions of the Soviet leadership in relation to the Baltic countries in May–June 1940.