This book is for all lovers ofmathematics. It is an attempt to under stand the nature of mathematics from the point of view of its most important early source. Even if the material covered by Euclid may be considered ele mentary for the most part, the way in which he presents it has set the standard for more than two thousand years. Knowing Euclid's Elements may be ofthe same importance for a mathematician today as knowing Greek architecture is for an architect. Clearly, no con temporary architect will construct a Doric temple, let alone organize a construction site in the way the ancients...