Stanislaw Patek (1866-1944) fulfilled the function of envoy to Moscow in the years 1927-1932, a period reflected in his copious documentation. The documents in question comprise an extremely interesting and valuable source for the history of Polish diplomacy, the history of the Soviet Union, Soviet studies, and international relations. Stanislaw Patek was proposed for the post of the Polish envoy by Marshal Józef Pilsudski, minister of foreign affairs in the cabinet of Kazimierz Bartel. True, after the May 1926 coup d'etat the minister of foreign affairs was August Zaleski, but the department was, for all practical purposes, steered by Pilsudski. Patek was entrusted not only with the mission of conducting a normalisation of Polish-Soviet relations, including a non-aggression pact, but also a Promethean campaign, i. e. supporting the decentralisation tendencies among nations comprising the Russian federation. The fact that Stanislaw Patek was an extremely careful observer of Soviet Russia stemmed from his duties as a diplomat and personal experiences in relations with the Russians, dating from tsarist times. He understood both Soviet policies and the tactics applied by the Russians in diplomacy and international relations. He also did not trust the sincerity of the disarmament campaigns undertaken by the Soviet diplomats. Although Patek appreciated the efforts made by Maxim Litvinov, the people's commissar for foreign relations, he did not harbour any illusions as regards his assurances concerning the peace policy of the Soviet Union. He was also deeply disappointed in the people's commissar Georgiy Chicherin, and his reports proposed a wide panorama of the domestic situation in the Soviet Union, including Stalin's struggle against the opposition in 1927. Patek analysed the Soviet system and policy in Europe and the world, and a crucial place in his reports is occupied by Polish-Soviet relations and the signing of the non-aggression pact of 25 July 1932, all presented within the wider context of international relations.