EN[...] The research object is the activities of the Seimas of the Republic of Lithuania, the Commission of Foreign Affairs, political groups and individual members and their impact on foreign policy during the period from 1920 to 1927, the relations between the Seimas and the Government solving the key issues of foreign policy and the attitudes of political groups and members of the Seimas on the issues of foreign policy. Though the history of the Lithuanian parliamentarism and diplomacy has received more attention in the studies of recent years, however, the impact of the Seimas on the foreign policy of Lithuania as a separate research object has not yet been thoroughly studied. Most attention has been paid to the works accomplished by the Constituent Assembly and the general political issues of the Lithuanian foreign policy - the issues of Vilnius and Klaipėda, the treaties with the Soviet Russia (later known as the USSR), the relations with certain countries as well as the biographies of the ministers of foreign affairs, diplomats and members of the Seimas. The activities of the Seimas seeking to solve the key problems of the Lithuanian foreign policy and its influence on the development of foreign policy have not yet received a consistent and comprehensive approach; the opinion of the political groups of the Seimas on the issues of foreign policy has been rarely analysed; the activities of parliamentary delegations abroad have received little attention as well. The studies on the history of the diplomacy of Lithuania usually attribute the establishment of the foreign policy to the ministers of foreign affairs and diplomats, whereas the contribution of the Seimas remains outside the scope of attention.This is the first monograph in the Lithuanian historiography and the history of parliamentarism, which attempts to analyse the activities of the Seimas of Lithuania in the context of the solution of the issues of foreign policy and its impact on the establishment of the course of the foreign policy of Lithuania from 1920 to 1927. The monograph presents the characteristics and comparison of the guidelines on the foreign policy of the country expressed by the parties, political groups and individual members of the Seimas and analyses the relations between the Seimas and the Government solving topical issues in this field. The analysis and assessment of the role of the democratic Seimas, individual political groups and members of the parliament in the establishment of the foreign policy of the country will contribute to the research of the history of parliamentarism. Besides, the inter war parliamentary experience in the area of foreign policy may find its niche in the present-day attempts of preserving and consolidating Lithuania’s statehood. The aim of the monograph is to analyse the activities of the democratic Seimas and its influence on the establishment of the course of foreign policy and the choice of geopolitical orientation and to assess its efforts in preserving the independence of Lithuania. The monograph also attempts to determine to what extent the Seimas was affected by the opinion of the public and the opposition. To achieve this aim, the following objectives have been raised in the monograph.To determine the competence of the Seimas and the principles of cooperation between the national authorities; to analyse the activities of the Constituent Assembly seeking the international recognition of Lithuania; to determine the issues solved in the area of the foreign policy, the impact of the Seimas in the drawing-up, discussion and ratification of the treaty with the Soviet Russia, the participation of the members of the Seimas in the negotiations with Poland and the political groups of Poles in Vilnius, the evaluation of the projects of Paul Hymans, the communication with the parliaments of the Baltic states; to analyse to what extent the Ministry of Foreign Affairs was influenced by the Seimas and what portion of its decisions was made independently. To analyse the position of the political groups and the representatives of national minorities of the First Seimas in the debate over the issues of foreign policy; to compare the position of the majority and the opposition in terms of the foreign policy of Lithuania; to analyse the attitude of political groups towards the incorporation of the Klaipėda Region; to find out how the opposition between the parties affected foreign policy. To explore the foreign policy guidelines of the political groups in the Second Seimas and the choice of international orientation; to analyse the debate over the Klaipėda Convention and the issues of integration of the Klaipėda Region in the Second Seimas, the position on the cooperation with Great Britain and the Baltic states as well as the relations with Vatican City and Poland; to determine and evaluate the activities of the political groups of the Seimas and the Commission of Foreign Affairs in the establishment of the concept of the foreign policy of Lithuania. [...]. [From the publication]