The opinion of the supervisor master thesis Kosenko Dmitry Vitalyevich "THE SOCIAL HISTORY OF THE DON COSSACKS (FEBRUARY 1917 – FEBRUARY 1919)".   Master thesis is devoted to the main period in the history of Russia. Unlike other research papers, the thesis focused on social history. Practically this is the first study in the social history of the Don during the the Civil War.  Variety of sources are to be noted. Archival materials. Periodicals. A memoir. The documentary edition. Many not previously published. The author clearly outlined the goals and objectives of the study are revealed in the work.             Sources allowed to create an independent scientific study that meets the requirements of the graduation master's thesis, Staint-Petersburg State University. Tasks and objectives of the study executed, a master thesis is independent. The work deservese the high praise.    Supervisor, Ph. D., Associate-Professor of Institute of history, St. Petersburg state University Ratkovskii I. S