The reviewer analyzes the ideas discussed in the book by Valery P. Leonov “The time of libraries”. Leonov’s study comprises 5 essays where the category of time is examined in the context of its perception in the humanitarian disciplines (library science, bibliography). Based on research publications, he identifies the models of time, namely functional, grammar, infinitive, speculative, verbal, mathematical, and constructive) and analyzes time – space and time – memory relations. V. Leonov concludes that time is not just the physical measure but also human subjective perception related to his or her personal memories and experiences. Time is characterized by sequence of events, circularity, distinguishing of the past, present, and future. Here the link between time and memory, transformation of possibility into reality are observed. Valery Leonov substantiates the importance of time cate gory for the librarianship and bibliography. The libraries operate in the changing sociocultural environment, so they can be characterized in temporal relations. The reviewer emphasizes the relevance of Leonov’s book that covers the wide range of problems and, in particular, the new aspеct of library studies within the space – time continuum.