Personal libraries of academicians always played an important role in scientific and pedagogical creative work. At the beginning of the 21st century, it is still true but the digitalization has changed the form and contents of the libraries. Personal libraries have become hybrid and now include not only printed or hand-written books but also electronic materials. In literary and book studies, library science, history, and cultural studies, there is a wellestablished tradition of studying personal libraries. But personal digital libraries only recently came into the scientific focus. Researchers from different scientific fields show interest in personal digital libraries, but the holistic comprehension of this phenomenon is yet to be reached. This paper is focused on the individual practices of creation, usage, and preservation of digital libraries of academicians. We are particularly interested in revealing correlations between the materials from the personal digital libraries and the research and teaching activities. For our research, we interviewed 19 employees of Tomsk State University who have a degree of Candidate or Doctor of Sciences and work in different scientific fields. The interview analysis showed that educators and scientists accumulate a number of digital documents that can be viewed as their personal digital libraries. But it is almost impossible to make a clear distinction between a personal digital library and a personal digital archive. The interviewees form their libraries in the course of their professional activities. During these activities, they often need to address their libraries which can be tracked both in the materials and in the text based on them. Academicians keep files in different formats but they prefer text formats (doc/docx, PDF) that allow editing and do not require additional software or devices. Personal digital libraries are mostly formed via downloading materials from the internet, scientific journals' websites, library databases, copying something from colleagues, or digitizing paper materials. One of the features of personal digital libraries is that the materials are stored distributedly. The extent of the distribution may vary depending on the age of the interviewees and its structure changed with time: if a few years back the materials were divided between different types of external storage, now most of the materials are kept in the cloud but in different accounts and services. Using the materials from personal digital libraries as primary sources can bring interesting results as, because of their digital nature, they can help to reconstruct the creative work of a scientist or a lecturer in a very real way. However, to make sure that the information potential of these sources is fully used, researchers need to broaden the variety of their own research instruments.
