Janusz Tondel - Professor emeritus of the Nicolaus Copernicus University in Torun. In his long-term research on early books, his principal focus has been on incunabula and the bibliophilic culture in Prussia and Königsberg in particular. Arkadiusz Wagner - art historian and book researcher at the Nicolaus Copernicus University in Torun. His main research area is the artistic value of medieval and modern books with a special focus on their bindings.