The documents of private origins in the collection of modern libraries demand specific workflow management, i. e. in interaction with owners, digitization, acquisition, cataloguing, access provision, and use. The Presidential Library as a national library of the Russian Federation integrates digitally the country’s historical and cultural heritage. Its digital collection “The Memory of the Great Victory” comprises over 1,500 letters of the Great Patriotic War period (1941–1945), i. e. letters from the front-line, letters by blockaded Leningrad residents, letters by evacuees, and other correspondence. The authors generalize the Presidential Library’s unique experience with private documents (war-time letters), including the specific character of acquisitions and cataloguing. The discussed approaches would enable to improve coverage of unique historical sources, to design new methods and instruments for handling the documents, to improve methodological support of cataloguing and indexing of this category, and to provide efficient access to library resources with new horizons for scientific research.