"La Philosophie de l'histoire" is an essential piece of Voltairean doctrine, but it has always been a somewhat neglected work, partly due to Voltaire's decision to incorporate it in the "Essai sur les moeurs". This edition restores Voltaire's original conception of the work, in order to restore its separate identity, to describe the genesis and elucidate the meaning of the work, to trace the ways in which it was later modified and to estimate its importance for Voltaire's thought and for the development of modern historiography.