Methodology of the history of the Ukrainian bibliography of M. I. Yasinsky

Considered the bibliological heritage of the Ukrainian scientist M. I.Yasinsky (1889-1967) on the subject of novelty in the methodology of the study of the history of bibliography in Ukraine. The stages of scientific and professional activity, in which the process of creative evolution of scientific thought of the scientist passed was realized. The content of the methodological concept concerning the history of bibliography. Conclusions are made regarding the social origins of the formation of a scientific concept.