DESCARTES, René. Principia philosophiae. [followed by] Specimina philosophiae. Amsterdam, L. Elzevier, 1644. In-4. 11 ff, 1 engraved portrait hors-texte, 310 pp, 1 blank sheet - 8 ff, 331 pp, 1 blank sheet. Bound in full vellum with contemporary covers, gilt fleuron in the centre of the boards framed by fillets. First edition of Descartes' Principles of Philosophy, written in Latin and translated into French in 1647. In addition to an engraved hors-texte portrait of René Descartes, the work is illustrated with numerous technical and geometric figures on wood. Guibert, 1 p. 118. Specimina philosophiae is the original Latin edition of the Discourse on Method from 1637. This translation was first made by Estienne de Courcelles, but Descartes wanted to make several changes. This text is therefore the one revised by the author. The Discourse on Method occupies 70 pages, the Dioptric from pages 71 to 206 and the Meteors from pages 207 to 331. The text is also illustrated with numerous in-text woodcuts. Guibert, 1 p. 104. Expert: François Giard See also the long notice of Willems (1008) who specifies that these two texts are usually bound in a single volume. A fine copy - very fine contemporary annotations in pen and pale red ink in the margins of the first text. Expert: François Giard