This is the first of two volumes of The Collected Works of Spinoza, which will make available, for the first time in English, a truly satisfactory edition of all Spinoza's writings, with accurate and readable translations based on the standard critical edition of the original texts. The editorial apparatus--prefaces, notes, glossary, and indexes--assists the reader in understanding one of the world's greatest but most difficult philosophers. Of particular interest is the glossaryindex, which provides, in an unusual format, considerably more information about Spinoza's use of his technical vocabulary than one is accustomed to finding in a translation. The first volume contains Spinoza's single most important work, the Ethics, and four earlier works: the Treatise on the Emendation of the Intellect, the Short Treatise on God, Man, and His Well-Being, Descartes' "Principles of Philosophy," and Metaphysical Thoughts. Also included are Spinoza's letters from the periods when these works were being composed.