Since the very inception of History of Science as a modern discipline, there was a concern with the organization of knowledge. The dialogue held by historian of science George Sarton and bibliographer Paul Otlet represents an illustrative example of this concern in the early decades of the 20th century. It is no reason for surprise then, that the classification developed by Sarton for Isis bibliography shared some common elements with the Universal Decimal Classification formulated by Otlet and Henri Lafontaine, more particularly, the place of disciplines as the backbone of classification.

However several factors were identified that make discipline-based classifications problematic. First the intrinsically interdisciplinary nature of History of Science itself, which crosses over at least history, philosophy, and the sciences themselves. Then, the historical trajectory of scientific disciplines, because as newer and more specialized disciplines emerge, other and more older ones become outdated, to disappear from the so-called “trees of knowledge”. Finally, the fast development of fields of knowledge crossing over disciplinary borders.

At the time when the main concern of bibliographers was how to place books and other documents in actual library shelves, that problem could hardly be addressed. However, the situation changed dramatically together with the introduction of information technology (IT), and the development of relational databases.

In the 1920s, Indian mathematician R. S. Ranganathan, after a season of training as bibliographer in London, developed a proposal for organization of knowledge based on strains of facets articulated by means of logical operators that transcends the rigid borders of disciplines and fits with the ethos and patterns characteristic of our “digital world”.

Repositories of primary sources for studies in History of Science might benefit from the application of facet-based classifications. In the present study, we address the application of faceted classification to one such specific repository, namely the one of Center Simão Mathias of Studies in History of Science (CESIMA), Pontifical Catholic University of Sao Paulo (Funding: CNPq 474061/2010-8; FAPESP 2011/14040-9; CNPq 309691/2011-7).