The article presents the codification of current approaches to the study of the library as an object of library science. Codification solves two interrelated tasks ‒ the refinement of content and form, means the official recognition, description and systematization of the basic directions of modern library science for its development and meets the most important needs of today. Within the current approaches, a systematic approach has been elaborated, which helped to substantiate the study of the library as a systematic object of library science, whose integral components are interdependent elements, and a model approach to the study of library interaction, as a complex open dynamic system and its separate sub-systems. The development of scientific libraries as a system, which is inherent in enhancing the unity and interdependence of all its elements, needs to be studied from the standpoint of a systematic approach. Neither library fund, nor users, nor staff, nor material and technical facilities it its own, nor even their interactions, viewed in isolation from one another, yet form the library as a coherent system. An organic whole is formed only when there are stable interconnections between these subsystems, which gives the system integrative qualities. A modern library is a system with internal and external interactions and connections between them, which is focused on external query, organization of library information resource, library services and products. The presented business model takes into account the individual characteristics of libraries, their ability to correspond to modern ideas about the library of the knowledge society. The argument is made that the works presented in the light of the problem presented in the headline, on the one hand, do not actually consider the interaction of libraries as the basis of its mission, and, on the other, represent library multifaceted evolution as an object of librarianship in time and space in context of social transformations.