 The authors were Antoine Arnauld and Pierre Nicole, philosophers and theologians associated with the Port-Royal Abbey, a center of the heretical Catholic Jansenist movement in seventeenth-century France. The first edition appeared in 1662; during the authors’ lifetimes four major revisions were published, the last and most important in 1683. The 1981 critical edition by Pierre Clair and François Girbal lists 63 French editions and 10 English editions (the 1818 English edition served as a text at the Universities of Cambridge and Oxford). The work treats topics in what are now regarded as the theory of knowledge, metaphysics, philosophy of language, grammar, philosophical logic, and both formal and informal logic. The Logic is a companion to General and Rational Grammar: The Port-Royal Grammar, written primarily by Arnauld and “edited” by Claude Lancelot, which had previously appeared in 1660.