The monograph examines the history of relations between Poland and Czechoslovakia in 1933-1939. Both West Slavic states were part of the Versailles-Locarno system, objectively directed against Soviet Russia. The main task of the diplomatic departments of both countries during this period was to avoid the possible movement of the ‘German factor’ to the East. Czechoslovakia was a bourgeois democratic state that sought to resolve foreign policy issues peacefully. In Poland, since 1926, a military-bureaucratic regime of ‘sanation’ was established, headed by J. Pilsudski, the main goal of which was to create a great power 'from sea to sea.'