This collection continues a four-volume series of sources on the history of the national liberation war of the Ukrainian people of 1648-1658, primarily archival, identified in Polish archives. Sources shed light on the then military-political events, illuminate the heroic struggle of the Ukrainian people for freedom and state independence. Sources are mainly presented in the original language (translated into Ukrainian). In this volume, the section "Materials" has been added, which contains some articles of the compiler of a predominantly source study nature concerning the Pereyaslavskaya Rada 1654