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books.google.com - In Proclus' penetrating exposition of Euclid's method's and principles, the only one of its kind extant, we are afforded a unique vantage point for understanding the structure and strenght of the Euclidean system. A primary source for the history and philosophy of mathematics, Proclus' treatise contains...https://books.google.com/books/about/A_Commentary_on_the_First_Book_of_Euclid.html?id=JZEHj2fEmqAC&utm_source=gb-gplus-shareA Commentary on the First Book of Euclid's Elements