This seven volume set, published for the first time in paperback, is intended to give in as complete a form as possible the correspondence of Isaac Newton. The project to bring Newton's correspondence to the public domain began in 1947 when the Newton Letters Committee was founded at the Royal Society, with the following principles being adopted for the work: to include all letters written by Newton; all letters addressed to Newton (both to be published in extenso); extracts from contemporary letters referring to Newton; and shorter memorabilia illustrating the life of Newton, particularly minor and hitherto unpublished manuscripts of Newton. To supplement the correspondence, there are notes throughout the series which provide connecting links relating to any given letter, as well as those of a biographical and bibliographical nature. There are also elucidatory notes that contain explanations of language, symbols and obscurities. Mathematical formul are also explored, showing a richness and depth of analytical theory in Newton's letters even where more mundane matters are being discussed. Letters originally written in Latin are for the most part reproduced with a full translation, or else by a short paraphrase, in English. The spelling, punctuation, use of capital letters and abbreviations are retained, as far as possible, just as the author wrote them.