The article analyzes the monograph of the Polish historian Jaroslaw Durka, "Janusz Radziwiłł (1880-1967). Political Biography", translated into Ukrainian from the Polish edition, published in Warsaw in 2011. J. Durka is a Doctor of Historical Sciences and researcher at the Kalisz Academy President Stanislaw Wojciechowski, an author of numerous publications related to the Radziwiłł family. The book describes the political biography of one of the brightest figures of Polish conservatism, Prince Janusz Radziwiłł, a parliamentarian of the Second Polish Republic [II Rzeczpospolita], an aristocrat, a person whose life absorbed all the significant events of the social and political life of Europe at the end of the 19th century – the 1960s. The monograph uses a vast source base, which includes documents from the Central Archives of Modern Records, the Central Archives of Historical Records, and the Central Military Archive (Warsaw), state voivodeship archives, in particular, Częstochowa, Kalisz, Katowice, Kraków, the Ossolinski National Institute in Wrocław, etc. The research examines publications from interwar periodicals, oral testimonies collected directly by the author, memoirs, published documents, etc. The author of the monograph highlights the traditions of the Radziwiłł family, the formation of Janusz Radziwiłł’s worldview and his political career, paying attention to his activities during the First World War, focusing on Janusz Radziwiłł's public and charitable activities in interwar Poland, the life of the last owner of the town of Olyka during the Second World War. One of the chapters draws attention to the final period of the life and activity of Janusz Radziwiłł, which he spent under the supervision of the special services of the Polish People’s Republic, practically outside of politics. J. Durka’s monograph, translated into Ukrainian, reveals little-studied pages of the history of Poland and Ukraine at the end of the XIXth – the first half and middle of the XXth century, prompting researchers for new scientific studies in the field of historical biography.