I am writing my dissertation on Newton and have found this translation incredibly helpful and surprisingly readable.<br><br>The Principia is one of the most difficult and inaccessible books ever written -- so much so, in fact that even John Locke (himself a pretty smart guy) had to ask Christian Huygens to explain much of it to him.  This difficulty was intentional, because Newton did not want people who only understood math a little to try and undermine his arguments. For this reason, he rewrote book three so that only those who had read and understood book 1 could understand its concepts.<br><br>People laugh when I tell then that I own a book with a three hundred page introduction, but it's a book that needs a three hundred page intro. In their intro, Cohen and whitman describe the history of the principia, its structure, an explanation of where prior translations have fallen short, and -- most importantly -- note which of the Principia's sections have been most significant during and after Newton's time. This is helpful so that when you get to each section, you are more likely to notice which elements may have seemed most controversial, where he is taking down Descartes' vortices, etc. I'm not saying I agree 100% with cohen and whitman on all of their points, but they have produced a work that does not simply translate the book; it also shares the writers' substantial knowledge about the principia.<br><br>This is an essential and monumental translation. If you are at all interested in early modern science, you must own it.