At the present stage of development of Ukrainian historical science, increasingly greater attention is paid to the study of sources of personal origin. In Western scholarship, they are regarded as ego-documents and are more important for the reconstruction of the past, both distant and recent. In many cases the documents of this group are the central ones. It is noted that the letters, as a historical source, are sources of personal origin and have their own specifics. Scientists have repeatedly emphasized that it “consists, firstly, in a vivid manifestation of the subjective perception of events, requiring a scientific critical attitude to this source; secondly, each epoch and each period of history left its mark not only on changes, but also on the form of letters”. Therefore, to study the relationship between different historical and political figures of a particular epoch, it is necessary to use ego-documents, in particular correspondence. It is emphasized that people’s letters to each other, being sources of a unique nature, express not only their instantaneous reactions to events, but also allow reconstructing the system of their relationships through arguments and evaluations of certain events and ideas. Furthermore, correspondence materials have an essential characteristic: being part of the context of human life, they are at the same time authentic sources for the formation of scientific ideas about this context. It is possible to create a complete picture of the activities of individuals in difficult periods of history only by considering the specifics of this context. The published letter reflects the political position of one of the prominent figures of the Ukrainian national liberation movement at the beginning of the 20th century, Volodymyr Levynskyi.