This article analyses the Diaries of the outstanding Russian historian Mikhail Bogoslovsky, a professor at Moscow Imperial University. The authors reveal the peculiarities of this unique historical source, largely filling in the gaps and lacunae of the archival materials and documentary publications that contain the official assessment of certain events. Bogoslovsky offers a wide panorama of events and facts, and not only his personal story: one may find an assessment of many of the events of his era, as well as of public authorities, representatives of the imperial administration, deputies of the 4th State Duma, and leaders of political parties. The article analyses Bogoslovsky's pedagogical activity and substantiates the thesis that among his diverse occupations, scholarly work was of primary importance for the historian. The authors focus on the peculiarities of the historian's relations with his colleagues and students. Special attention is paid to the analysis of the work on his main study, a multivolume book on the life of Emperor Peter I. The article provides information on the daily life of the historian's family, which allows the authors to identify how the scholar mastered the new social practices which helped him, like many other city-dwellers, survive in the face of a growing crisis in all spheres of economic and sociocultural life during the period of revolutionary chaos. Between 1916 and 1917, owing to an increase in crisis phenomena, the everyday life of the population of Russia took another turn. In this context, influenced by periodicals, the diaries give an impartial assessment of the ineffective work of the imperial administration, the deputies of the 4th State Duma, and the local authorities. Comparing the past of Russia with its current reality, he makes attempts to predict the future of Russian statehood. The authors conclude that in trying to escape from the dramatic reality of his time, the historian increasingly began to turn to the historical situation of the 18th century.
