The training of scientific and professional staff in library science began in the 1930s in the structure of pedagogical science. The peculiarity of this process was the comprehensive coverage of library science and the inclusion in the composition of librarianship of a number of topics that were not pedagogical in their orientation. At the initial stage, comprehensiveness contributed to the formation and development of library science due to the organizational and methodological support of pedagogical science, but later it came into conflict with its subject field. In the 1950s, it was allowed to prepare library science dissertations in historical science, but in practice, librarians were unprepared for this expansion. In the 1970s, the training of scientific and pedagogical personnel in library science “moved” to the structure of technical sciences, to the group of specialities “Documentary Information” with permission to defend themselves in technical sciences. But in practice, the academic community in the field of technical sciences was not ready to accept library science, and the defense of this specialty continued in the pedagogical sciences.With the adoption of a new Nomenclature of Scientific Specialties, which are awarded academic degrees, the situation has changed. Library science was referred to the social sciences and humanities, to the group of scientific specialties “Art History and Cultural Studies”. A new edition of the passport for the scientific specialty “5.10.4 Library Science, Bibliography, Book Science” was adopted, in which 24 out of 40 research areas of library science are concerned, and only four of them can be directly attributed to pedagogical sciences. On the example of specific dissertations their pedagogical potential is revealed. As for the remaining 20 areas, with the exception of dissertations on the history of librarianship, organically included in the subject field of historical science, the question of their scientific and branch affiliation remains open. It is suggested that the practice of defending library science dissertations, not related to the subject field of pedagogy, in pedagogical sciences will be discontinued.It is stated that there are still contradictions in the passport for the scientific specialty 5.10.4 between the scientific directions of library science and the subject fields of the disciplines for which the preparation and defense of dissertations is established. The possibility of recognition by the expert community of the Higher Attestation Commission for Cultural Studies of the conformity of dissertation research on management and marketing of library and bibliographic activity and similar to them to the subject space of cultural studies is questioned. Attention is drawn to the actualization of the pedagogical content of library science through the inclusion of relevant topics in the list of relevant topics of dissertation research in the field of educational sciences.It is proposed, firstly, to develop research on library science, which is not included in the subject field of the disciplines specified in the passport, in other scientific disciplines. Secondly, the training of scientific personnel in library science should be conducted within the subject field of pedagogical science, focusing, if possible, on the directions we have identified. Thirdly, to intensify the development of the modern educational concept of librarianship, strengthening and strengthening the interaction between library science and pedagogical science by organizing joint scientific events, as well as the involvement of library scientists in the work to improve the Nomenclature of Scientific Specialties. Fourthly, it is necessary to improve the passport of scientific specialty 5.10.4 with regard to library science, taking into account the content of the subject fields of scientific branches, in which the preparation and defense of dissertations is established; with regard to pedagogical science — to expand the number of areas by including educational activities of libraries.