The book of Doctor of Historical Sciences, Professor V.I. Korolev is written on the basis of new and diverse sources, opens a new page in Crimean history, shows the organization, directions, forms and methods, the specifics of the activities of the gendarmerie and political investigation of Crimea in the fight against the revolutionary movement in the late XIX - early XX centuries. The monograph has not only scientific, cognitive, but also practical significance. It will help in pedagogical practice in the training of special personnel in higher educational institutions of the Ministry of Internal Affairs and legal universities, as well as replenish the baggage of historical knowledge of today's and future employees of these departments. This historical study will be interesting to a wide range of readers interested in the history of Crimea.