Euclid is famous the world over for his textbooks on geometry, which have been in use for two thousand years. His exactness and accuracy of method have never been surpassed. The principles of his brilliant introduction to geometry are contained in his immortal Elements of Geometry. It was this work that greatly extended the boundaries of mathematics and established the primary form of geometry until the past century. No other textbook has served as an introduction to a subject for so long a time. The present volume brings together what is known of this Greek genius, and traces the development of geometry before, during, and after his time.