The file cabinets of the Universal Bibliographic Repertory (RBU) are without doubt the best known part of the Mundaneum. They are also the most striking aspect of the museum design created by François Schuiten and Benoît Peeters. In 2013, the RBU was added to UNESCO’s Memory of the World (MoW) Register as a tool that made it possible to find any book in the world.
The RBU project was started by Paul Otlet and Henri La Fontaine in 1895. The idea was to list all the world’s publications on bibliographic cards, regardless of the subject, date or place of publication, or indeed the place they were held.
The RBU comprises two main parts: one onomastical (i.e. answering the question “What did such and such an author write?”), and the other thematic (i.e. classified by subject). In addition to these directories, there are other related directories, such as the Periodical Titles Directory and the Administrative Directory, which records correspondence, staff information, inventories of collections, and so forth on index cards.
Starting with a database of 400,000 records compiled by Otlet, La Fontaine and his sister Léonie, the RBU grew rapidly and by 1897, it contained 1.5 million records. In total, between 1895 and the mid-1930s, thanks to the contributions of a global network of bibliographers and librarians, the RBU contained some 18 million records.
For the thematic referencing, Otlet and La Fontaine developed the Universal Decimal Classification (UDC) system. Based on the decimal classification system created in the 1870s by the American librarian Melwil Dewey, the UDC divides knowledge into 10 classes numbered 0 to 9 (e.g. works on history fall into class 9). Each class is in turn divisible into 10 groups, each group into 10 divisions and each division into 10 sub-divisions, so that the subject of a book can be very precisely indexed. The advantage of this method over others is that it replaces a keyword by a numerical index. This avoids the difficulties of interpreting the choice of keyword and bypasses the obstacle of the language used, as numbers are, by definition, universal.
