Descartes's Principles 0. / Philosophy is his longest and most ambitious work; it is the only work in which he attempted to actually deduce scientific knowledge from Cartesian metaphysics, as he repeatedly claimed was possible. Whatever the success of this attempt, there can be no doubt that it was enormously influential. Cartesian celestial mechanics held sway for well over a century, and some of the best minds of that period, including Leibniz, Malebranche, Euler, and the Bernoullis, attempted to modify and quantify the Cartesian theory of vortices into an acceptable alternative to Newton's theory of universal gravitation. Thus, the Principles is not only of inherent and historical interest philosophically but is also a seminal document in the history of science and of 17th Century thought. Principles of Philosophy was first published in Latin, in 1644. In 1647, a French translation, done by the Abbe Claude Picot and containing a great deal of additional material and a number of alterations in the original text, was published with Descartes's enthusiastic approval. Unlike some English translations of portions of the Principles, this translation uses the Latin text as its primary source; however, a good deal of additional material from Picot's translation has been included. There are several reasons for this. First, there is good evidence that Descartes himself was responsible for some of the additional material, including, of course, the Preface to the French translation.