The foundation, development and activities of the Russian National Public Library for Science and Technology (RNPLS&T) are examined in the historical aspect. The precedent events, the origins of the library and development from the initial library collections in science and technology in the early 20-th century are described. The RNPLS&T (the USSR State Public Library for Science and Technology, SPLS&T USSR, at the time of its establishment) has inherited the legacy and, partially, the collections of the State Science Library. The authors focus on the evolution of the SPLS&T USSR as the head sci-tech library of the nation providing information support of new developing industrial technologies as well as prospective scientific disciplines. The authors offer information on current RNPLS&T activities, their vectors and performances; characterize the library collections, e-catalogs, digital archives and RNPLS&T’s e-library, as well as library and information services, educational activities and its large-scale international scientific and educational events. The publication is prepared on the occasion of the RNPL&T’s 65-th anniversary