Thomas Hobbes (1588-1679) is one of the most important figures in the history of European philosophy. Although best known for his political theory, he also wrote about theology, metaphysics, physics, optics, mathematics, psychology, and literary criticism. All of these interests are reflected in his correspondence. Some small groups of his letters have been printed in the past (often in inaccurate transcriptions), but this edition is the first complete collection of his correspondence, nearly half of which has never been printed before. All the letters have been transcribed from the original sources, and all materials in Latin, French, and Italian are printed together with translations in clear modern English. The letters are fully annotated, and there are long biographical entries on all of his correspondents, based on extensive original research. The whole pattern of Hobbes's intellectual life and personal friendships is set in a new light. This is one of the most significant and valuable scholarly publications of this century.