The article is about the value of archives and book collections belonging to scholars and conceived as sources for the history of the reception of new methodologies, the establishment of contexts, obtaining publications difficult to access, and the creation of milieus cooperating beyond all state frontiers and political systems. A distinct problem involves dedications inscribed in books as well as notes on margins and underlining. Studying book collections makes it feasible to follow the course of scientific discussions not recorded in official appearances and publications.