to realize the novelty of the Cartesian doctrine, and the enormous effect it had upon European thought at the time. He will further be able to judge better of the success of Descartes' attempts to extricate himself from the difficulties which his philosophy undoubtedly contains.
The works translated here are the "Rules," the "Method," the "Meditations," with the "Objections and Replies," part of the "Principles," the "Search after Truth," the "Passions," and the "Notes." Unfortunately it has been found impossible to include Descartes' philosophical correspondence and his more specially physiological treatises, but perhaps in the not too distant future the work of the present translators will be supplemented in this direction.
The translators have used the new and complete edition of Descartes' Works which has been prepared by M. Adam and the late M. Tannery (Paris, Léopold Cerf). The translator of the "Rules for the Direction of the Understanding" has also had recourse to an edition published by Dr Artur Buchenau (Leipzig, Dürr'schen Buchhandlung 1907). Moreover his especial thanks are due to Mr W. R. Boyce Gibson, who already had a translation of the work in manuscript, for kindly permitting him to use, as he did with great profit, this previous version.
E. S. HALDANE
G. R. T. ROSS
March 1911
