The project task was to collect oral witnesses about life of the Ukrainian Greek Catholic Church under the totalitarian regime, which was the biggest church community forbidden in the Soviet Union. Abolishment of the disobedient Church, which was organized by the Soviet Power and its repressive authorities, was fulfilled by so called Lviv “council” in 1946, according to its resolutions the Church stopped to exist officially and “was reunited” with the Russian Orthodox Church. (“Council” was organized by the agencies of the state authorities and NKVD (People's Commissariat for Internal Affairs) in collaboration with the members of «The Initiative Group on reunion of the Greek-Catholic Church with the Russian Orthodox Church”). This act of “reunion” was accompanied by the arrests of the Greek-Catholic clergy, monks, nuns and laity. UGCC, which was abolished and forbidden by the Stalin regime, began a new page of its history – the history of courageous and heroic resistance, indestructibility of spirit and tremendous strength of faith in Christ and His final victory. During the time of persecution, in a condition of a rigid underground, the Church was able to maintain its structure, apostolic succession of episcopacy and replace its ranks by the new faithful. After Stalin’s death the Greek-Catholic clergy, monks, nuns and laity came back from prisons. The life of the underground Church became more active – life of the monastic communities revived and future priests were studied at the underground seminaries.