Personalization Concepts of Library and Information Services Evolution in the International Research

In the context of digital transformation and rise of user expectations shaped by commercial online services, personalization of library and information services (LIS) is becoming a key factor for their relevance and demand. The purpose of this article is to systematize and analyze international experience in implementing personalization in LIS based on the review of scholarly publications. It traces the evolution of conceptual approaches: from early forms of Selective Dissemination of Information (SDI) and user-customized interfaces to modern proactive models based on artificial intelligence (AI) and the human-centered “Library 5.0” paradigm. The original periodization of LIS personalization concepts is proposed. The technological toolkit for personalization is systematized, including discovery systems, AI algorithms, and mobile technologies. Key barriers are analyzed: technological, organizational, staffing, and financial, as well as ethical challenges related to user data privacy and algorithmic bias. It is concluded that successful personalization represents a comprehensive strategic transformation that changes not only the service portfolio but also the role of the librarian in the digital environment.