Digital transformation of document arrays has changed the nature of information infrastructure, as the digital documents are created, distributed, discovered and delivered in principally other way than in the epoch of printed matters as the main information media. The transition to digital information infrastructure has resulted in the loss of role of libraries as an essential intermediate on the document author-to-reader way, reasonably displacing libraries to the periphery of information activities and depreciating the majority of methods and technologies of document array organization developed through the centuries. The author substantiates the rationale for degrading information component of library mission and the necessity to transit to prevalent analytical services. The decreasing role of libraries is determined by the following factors: reduction of overall printed publications; their lower contextual value; capabilities to store, distribute, process digital information array formally and semantically, information deliver to users without the input of librarian. Therefore, not all the manual processing operations have become demanded any more. The print arrays grow scanty quantitively and contextually, and the increasing and dynamical digital flows are processed by ever-improving software. The author sees the solution in expanding analytical function of libraries which envisages inclusion of professional competences related to complex analytical processes, i. e. fact search and verification; acquisition and processing of statistical and experimental research data, preparation of analytical surveys, reviews and reports.