Descartes' The World offers the most comprehensive vision of the nature of the world since Aristotle, and is crucial for an understanding of his later writings, in particular the Meditations and Principles of Philosophy. Above all, it provides an insight into how Descartes conceived of natural philosophy before he started to reformulate his doctrines in terms of a skeptically-driven epistemology. This volume offers a new translation of the work together with related writings that illuminate it, including the first English translation of the complete text of The Description of the Human Body.

The Treatise on Light and the Treatise on Man – which I shall refer to under the collective title The World – together constitute the most ambitious systematic project that Descartes ever undertook. Neither appeared in his lifetime. The first was published posthumously as Le Monde in, the second two years earlier as Renatus Descartes de Homine. Both are parts of what is ostensibly a single work, and form the backbone of a single treatise. The text went through a number of redraftings, not just with respect to the detail of the arguments but also with respect to what should be included in the treatise, and the project included not only the Treatise on Light and the Treatise on Man, but also the material on the formation of colours in the Meteors and the material on geometrical optics in the Dioptrics, both subsequently published in along with the Discourse and the Geometry. I have included this material as appendices to the text of the Treatise on Light. There are also indications that Descartes had originally intended incorporating other material, including some work on music, for example, although this is not extant and may never have been developed in a systematic way