The aim of this two-volume edition is to provide a completely new translation of the philosophical writings of Descartes, based on the original Latin and French texts. Although many of Descartes' philosophical works are now available in English either individually or in various selections, the only tolerably comprehensive edition remains that of Haldane and Ross, which first appeared in 1911. But although it has come to be regarded as the standard English edition, HR omits many works which are crucial for a full understanding of Descartes' philosophy. The present work, by contrast, aims to be as comprehensive as possible. Considerations of space have prevented us from being as inclusive as some, no doubt, would have wished; we have not, for example, included any of Descartes' letters, partly because an excellent selection is already available in English. But as well as including all the works to be found in Haldane and Ross, viz. the Discourse on the Method, Meditations, Objections and Replies, Rules for the Direction of the Mind, The Search for Truth, Comments on a Certain Broadsheet, The Passions of the Soul and selections from the Principles of Philosophy, we have also provided extracts from Descartes' Early Writings, from The World, Treatise on Man, Optics and Description of the Human Body; our selection from the Principles, moreover, includes many articles not translated in Haldane and Ross.