The book tells about the little-known and controversial phenomenon of 1917–1918 pp. - The Free Cossacks are a kind of Ukrainian paramilitary public organization that emerged and spread en masse, primarily among the peasantry. On the basis of documents found in the archives, a wide range of published sources detailed the causes and features of the Free Cossack movement, a comprehensive analysis of the Free Cossacks and, in particular, their activity during the military-political conflict between the Central Council and the RSFSR (December 1917-March). 1918 pp.) And the peasant-insurgent movement in the summer of 1918. and the Hetmanate, the kinship of the Free Cossack movement 1917-1918 pp. and otamans 1919–1920 pp., activities of emigrant “heirs” of the Free Cossacks in the 1920s – 30s, etc. In addition, many inaccuracies, errors and falsifications that exist in the historical literature on this topic have been identified. Many of the documents published in the appendix are introduced into scientific circulation for the first time. The book is intended for scientists, teachers, students and anyone interested in the history of Ukraine and the Ukrainian peasantry.