"(Professor Yaffe's) learned study of the treatise and his interpretations of its significance are simply among the most intelligent studies that one may find -- his devotion to researching the teachings of the treatise has encouraged the production of this new English translation of it which is unique and comprehensive... and is valuable to every reader of Spinoza at every level of ability. Indeed, I have every confidence that his translated edition of the treatise, together with the outstanding scholarly critical apparatus that it employs, will be acknowledged universally as the best English translation and edition of the work available..." -- Paul J Bagley, President, North American Spinoza Society.