Historiography of mass-circulation newspapers of the 1920s and 1940s as component of Soviet periodicals

Purpose. By means of the analysis of the historiography of the research of the history of the Soviet press and mass-circulation newspapers as its component, to reveal the potential of this type of publications as a complex historical source, the object of press and bibliographic research; identify the features inherent in these newspapers depending on the time of their publication: the subject matter of publications, external features, quantitative characteristics of newspapers of the 1920s are significantly different from those published in the late 1930s - early 1940s. If the 1920s were a period of formation and development of the mass-circulation press such as newspapers for workers and employees, in the late 1930s they became bodies of the party committee, directorate, executive committee, and finally established themselves as effective tools of Soviet printed propaganda and agitation for all population segments. The methodology is based on the principle of historicism; a set of methods is used: historical and chronological, comparative and source analysis. The novelty lies in the presentation of mass-circulation newspapers as a separate type of historical sources and bibliographic object, which is part of the repertoire of periodicals and, more broadly - part of the retrospective national bibliography of Ukraine. A new set of sources is introduced into the information space enabling to expand the source base of periodical press research. Conclusions. The article proves that the array of mass-circulation newspapers requires a comprehensive study: determining the theoretical and practical principles of origin, development and operation, organization of their storage in library fonds, providing access to this information resource to all categories of users. The inclusion of this type of periodicals in the range of historical sources is relevant given their source potential; a practical step towards their introduction into scientific circulation and information is reconstruction.