Very little is known of the ancient mathematician Euclid. except that it is believed that he taught in Alexandria in Egypt. Indeed, there is even doubt about whether Euclid existed as an historical character, or whether a group of mathematicians wrote under the name.
Euclid is best known for his fundamental work on geometry, The Elements, certainly one of the most widely studied and influential mathematics books of all time. This work is remarkable for its modern approach, with carefully stated axioms and with theorems carefully derived from the axioms.
A number of other books are attributed to Euclid, including works on graphical constructions, optics, astronomy, and fallacies.