The purpose of the article is to actualize the idea readers’ satisfaction with organization of work and quality of library and information services provided by the largest beyond the Urals information institution – State Public Scientific-Technological Library of the Siberian Branch of the Russian Academy of Sciences (SPSTL SB RAS). Data collection was conducted in 2023 by face-to-face questionnaire. The survey questions allowed the respondents to rate the library work in points and to express their opinions in a more detailed way. The responses gained were analyzed on quantitative and qualitative levels. The numerical results of the survey gave an overall picture of the readers' preferences and the level of their satisfaction with the library services. Qualitative analyses of the respondents' extended responses contributed to a deeper understanding of the essence of views expressed in them. Basing on the obtained data it was found that the readers of SPSTL SB RAS in general highly appreciated its collections and professional qualities of its staff, considered the conditions of staying in it comfortable. Nevertheless, the complaints expressed by the respondents about the electronic catalogues, the library website, the system of informing about the available services and facilities require prompt response of the relevant library departments. The results of the research allowed us to get the "portrait" of the contemporary SPSTL SB RAS reader, to identify strong and weak aspects in working with him and to formulate proposals that contribute to solving a number of identified problems and determine further steps to improve the library service system.