Meditations on First Philosophy
Principles of Philosophy () is a book by René Descartes. In essence, it is a synthesis of the "Discourse on Method" and "Meditations on First Philosophy". It was written in Latin, published in 1644 and dedicated to Elisabeth of Bohemia, with whom Descartes had a long-standing friendship. A French version ("Les Principes de la Philosophie") followed in 1647.