ENAfter the end of the Second World War, a rather long Soviet occupation began in Lithuania. This was a difficult period of trials for the entire Lithuanian society, and especially for the Catholic Church. Any possibility of permanent training of clergy was then forbidden. In this way, Catholic priests in Lithuania learned to act underground. The need for spiritual and intellectual improvement was not just an individual affair. During the long years of Soviet occupation, certain schools were formed to provide assistance to the priests of the persecuted Church. Such schools became secretly operating monasteries. Lithuanian priests drew courage from the personality of Pope John Paul II, as well as new ideas from underground publications and books imported from abroad, especially from Poland. Soviet atheist propaganda, which persecuted priests and wanted to turn them into people without higher education and present them as such in society, did not achieve its goals. Keywords: priests, self-education, Soviet occupation, books, theology. [From the publication]