Today, the pace of transition to information society, based on information and knowledge, is accelerating. The authors emphasize the difference between digitization (conversion of analog information resources to digital formats) and digitalization (initial generation of information resources in digital formats). Digitalization has initiated the process of digital transformation (DT). The DT results in qualitative changes in economic and social infrastructure (which includes the library information sector), and public administration. The authors analyze the concept and vectors of digital transformation in libraries (DTL). The DTL achievements are assessed against the Stolyarov’s four-component library model that is still relevant. The digital transformation in libraries is the transformations in the library information sphere that make it to revise its activities conforming to the comprehensive digitalization paradigm. The authors discuss the key DTL components to characterize the transition of libraries to information society.