Euclid fl.300BC
Greek mathematician

He taught in Alexandria, where he appears to have founded a mathematical school. His Elements of geometry, in 13 books, is the earliest substantial Greek mathematical treatise to have survived, and is probably better known than any other mathematical book, still being used as the basis of school textbooks in the earlier part of the 20th century. It was the first mathematical book to be printed and has stood as a model of rigorous mathematical exposition for centuries. It covers the geometry of lines in the plane, including Pythagoras's theorem, and goes on to discuss circles, ratio, and the geometry of three dimensions. He wrote other works on geometry, including the theory of conics, and on astronomy, optics and music.

Bibliography: Henry Albaugh, Euclid (1971)