The book THE UNKNOWN WAR highlights the dramatic events of the worst (more terrible than World War II) war for Belarus, which for political reasons remained practically unknown to us until recently. Based on documents and research, the author describes the real goals of Muscovy's intervention and the occupation policy of tsarism in Belarus, talks about battles and siege of cities, for the first time shows a broad movement of popular resistance to strangers, tries to determine the place of the war of 1654-1667 in Belarusian history.