The monograph focuses on Catholic parishes in the vicinity of the place called Sapotskin located at the junction of the Belarusian, Polish and Lithuanian borders. The authors' interest in the subject was not incidental, since the Uniate Church survived longer in the area. The Russian authorities banned the Greek Catholic Church in 1839 and forced its followers to convert into Eastern Orthodox believers. But residents of this area continued to worship in Uniate churches until the end of the century. As time went by, many of them adopted Catholicism and called themselves Poles. But locals still think they differ from the Poles living west of Belarus and consider Belarusian their mother tongue. The authors conclude that Sapotskin residents use the word "Poles" to describe their sociocultural status rather than nationality.