Based on rich archival materials, including those not published in scientific literature, the author reconstructs the events of the early 20th century. and talks about the participation of the Don Cossacks in the Russo-Japanese and First World Wars. The book convincingly refutes the opinion of Soviet and Western historians that the role of the Cossacks in the military operations of the Russian army was insignificant and they performed mainly police functions. As an appendix, the book includes two issues of documentary stories and essays “Our Cossacks in the Far East” for 1907 and 1910