This is an English translation of important writings on the Thirty Years' War by the great Soviet historian B. F. Porshnev. Little is known of the Muscovite contribution to the conflict and Paul Dukes - arguably Britain's senior historian of ancien regime Russia - has selected the most valuable areas of Porshnev's unparalleled archival research to fill a crucial gap in the literature of the seventeenth century. In placing this work in the context of Porshnev's larger undertaking, Professor Dukes' substantial introduction assesses Porshnev's critics and evaluates his contribution to our understanding of the Thirty Years' War and of relations between Eastern and Western Europe at the time. A significant reinterpretation of a fascinating period, the book will interest both Russian specialists and those working more generally in seventeenth- century European history.