The article is devoted to the 90th birth anniversary of E.A. Fenelonov, the prominent figure of library construction, scientist-librarian and the Honored worker of culture of the RSFSR. The authors present his biographical data, data on the most important stages of his life and activity: study at the Moscow State Library Institute, postgraduate study, defence of the dissertation thesis “Organization of library service for rural population”, leadership of the newly organized library of the Lipetsk region; work as the Head of Department (then Division) of libraries of the Ministry of Culture of RSFSR, the Head of the Main information-computing centre for culture and arts of the Ministry of Culture of RSFSR, the Deputy Director for scientific and methodical work of the V.I. Lenin State Library of the USSR (nowadays — the Russian State Library, RSL), the research scientist in the Research Department of the RSL. The paper describes the general characteristic features of his administrative activity and scientific creativity. The authors emphasize his role in the centralization of the library network, creation of depository libraries, introduction of open access and computers in the librarianship, participation in the development of the “Regulations on Librarianship in the USSR” (1984), the laws “On Librarianship”, “On the Legal Deposit Copy of Documents”, etc. The paper considers the main works of E.A. Fenelonov, dedicated to the management of librarianship, comprehensive planning of library construction, economic efficiency of libraries, organization of the library network, library zoning, activities of the centralized library systems, methodical work of libraries. The authors reveal the personality of E.A. Fenelonov as organizer, manager, scientist and person.