The contributions included in this volume address issues related to contemporary problems of publishing archival sources, legal aspects of access to archival sources created in the 20th century, electronic documents – their mass nature, peculiarities and gaps in the 20th century documentation, as well as sources serving to transfer values and knowledge between generations. The archives described in the articles cover a wide spectrum of issues concerning both the everyday life of outstanding individuals and documentation of fundamental importance for the development of civilisation, shaping international relations and relationships, and constituting geopolitics.