Abstract
As a general introduction to Ockham’s commentaries on logic, that of Porphyry and Aristotle, the Expositionis in libros artis logice Prohemium deals with the nature of this discipline, its subject, its utility, its specificity, and of its epistemological status. The new French translation offered here is accompanied by an annotated edition that reproduces the medieval spelling of Ockham’s Latin. The same goes for the new translation of the beginning of Ockham’s first logical commentary, the Expositio in librum Porphirii De predicabilibus, whose highlight is the interpretation of Porphyry’s questions on universals (genera and species).