This article examines the phenomenon of informal education as a key component of continuous professional development, particularly in the context of research. The aim of the study is to define the concept of “informal education of researchers” and identify the role of libraries in this process. A terminological analysis of domestic and international literature has resulted in the following definition: this is a purposeful and professionally significant cognitive activity, regulated by a researcher him(her)self, aimed at acquiring new knowledge and skills (especially in the context of open science), using information and communication technologies in a digital environment, and characterized by awareness, consistency, and independence. Particular attention is given to the transforming role of scientific libraries in this process in the digital age, they are becoming active content providers and multifunctional educational centers. Libraries not only provide access to resources but also offer various services, including training in information literacy and research data management, support for publication activities, and assistance in using digital tools. The “Library for Open Science” platform (State Public Scientific and Technological Library of the Siberian Branch of the Russian Academy of Sciences) is cited as a successful practical example, demonstrating how comprehensive online services, guides, and training materials support the informal education of scientists. It is concluded that integrating libraries into informal education is a necessary condition for improving the effectiveness of scientific research.
