The published collection contains articles by young scientists, which develop little-researched problems of source study and the history of the formation of one of the special historical disciplines - genealogy. Other works consider problems that already have a solid historiographic tradition, but unlike the works of their predecessors, the authors of these articles approach their study in a new way, revise some questions, and introduce new points into their research. All articles of the collection to one degree or another are related to the work of the Sector of Source Studies of the History of the USSR in the pre-October period of the Institute of History of the USSR Academy of Sciences of the USSR.