This is an impressive work of scholarship &amp; I highly recommend it to all serious students of physics.<br> The authors set out to produce a modern translation of the third and final version of Newton's masterpiece which was originally written in Latin and published in 1726.<br>The first &amp; only complete English translation of the Principia, before this new translation was made, was by Andrew Motte in 1729 - only three years after Newton's work in Latin appeared.<br>Motte's translation was revised and "modernized" several times in the intervening 270 years, the last being in the mid 1800's but it still was regarded as being almost as difficult and opaque as Newton's original.<br>This new translation by Cohen &amp; Whitman is really two books in one. The first 370 pages of the 966 page work is "A Guide to Newton's Principia" and consists of eleven Chapters that explain the structure of Newton's work and how to read it. This part is indispensable to the modern reader. The last 596 pages is a careful translation into modern English of the original Latin version.