In Viktor Sokolov’s article «Bibliographic research in the national libraries of Ukraine in 2016–2020: a summary analysis» based on the analysis of materials of scientific publications and reports on the scientific research work of national libraries, the state and directions of the development of bibliographic research are summarized and highlighted using the example of the characteristics of the study books in certain specified institutions. The article clarifies the place and significance of bibliographic research in the study and popularization of specialized funds of national libraries, as well as in the preparation of relevant materials for the State Register of National Cultural Heritage; the topics, peculiarities of conducting and organizing bibliographic studies in the researched library institutions are disclosed; the importance of the study of rare and valuable books, library collections and book collections for the development of national culture is confirmed. The purpose of the proposed article is to characterize the content and directions of bibliographic research carried out in the national libraries of Ukraine in 2016–2020. The research methodology consists in applying both general scientific research methods (description, comparison, analogy, deduction, induction, analysis, etc.) and historical ones (historical-comparative, historical-typological, chronological, etc.). The scientific novelty of the work is that the state and nature of bibliographic research in the national libraries of Ukraine in 2016–2020 was analyzed for the first time; their place and importance in the research work of the mentioned institutions is substantiated. Conclusions. It is substantiated that in the period 2016–2020 in the national libraries of Ukraine, the development of scientific research work in the field of bibliography was characterized by the activation of research in historical, theoretical and methodological directions, among which, in particular, the issue of the creation and functioning of the book as a type of communicative- cognitive tool occupied an important place activities aimed at meeting information needs by means of printed and electronic information. It has been established that the specified bibliographic studies can be classified: by the nature of scientific knowledge into fundamental and applied; according to the scope or limits of the implementation on local, regional, national level; according to the time of implementation into permanent and episodic. It has been proven that medium-term local applied scientific research, designed for 1–3 years, prevailed, and the subject of bibliographic research was aimed not only at ensuring the disclosure of the informational and source- research resource of book funds, but also at solving theoretical fundamental scientific problems. Based on the analysis of the topics of scientific projects, publications and reports at scientific and practical conferences organized by national libraries, it is substantiated that a significant part of bibliographic research was devoted to the historical aspect of the development of book collections and the libraries themselves; analysis of a set of prints by a certain feature; study of individual types and types of publications. It was found out that studies related to bibliography were actively developing, in particular, in the art of books, book historical studies, publishing history, bibliographic studies, library history, Ukrainian history, and other fields of social sciences. It is motivated that bibliographic studies contribute to the mutual enrichment of these sciences, significantly expand the cognitive capabilities of their methods, and have a positive effect on the improvement of theory.