ENThe present volume of documents, “Soviet security services against the Polish and Lithuanian independence underground in 1944-45”, is the collective result of the work of Polish and Lithuanian historians and archivists from the Institute of National Remembrance in Warsaw, the Genocide and Resistance Research Centre of Lithuania, and the Lithuanian Special Archives in Vilnius. This is the first volume in the new series, “Poland and Lithuania in the 20th century. Documents from the archives of the secret services”. The anthology presents NKVD-NKGB documents and depictions of the processes used by Bolsheviks in the conquest and occupation of territory in present-day Lithuania and in the Vilnius region (which was within the limits of the Second Polish Republic until 1939), the repression inflicted on the structure of the Polish and Lithuanian armed and political independence movements, and the arrest, murder, and deportation of the military and social elite to concentration camps, as well as the deportation of the families and supporters of Polish Home Army troops and Lithuanian underground forces to labour camps.Soviet and Russian historiography calls this period the “liberation”. The published documents primarily come from Soviet security services. The volume also includes a sampling of documents made by the Polish and Lithuanian independence underground in their attempt to resist against Soviet occupation, which was characterized by mass terror against the inhabitants of the occupied territories. These materials are currently being stored at the Lithuanian Special Archives in Vilnius. This volume also includes an apparatus criticus featuring, among other things, biographies of soldiers of the Polish and Lithuanian independence underground, biographies of Soviet security officers, as well as footnotes explaining historical terms and concepts. The next volume in this series is currently under preparation.