His chief work, entitled Elements, is a comprehensive essay on mathematics. It includes 13 volumes that entail such subjects as plane geometry, dealing with the properties of flat surfaces and of planar figures, such as the triangle; proportion in general, a particular kind of relation between groups of numbers or quantities; the properties of numbers; incommensurable magnitudes; and solid geometry, branch of geometry that deals with the properties and measurement of geometric figures in three-dimensional space. Some people say that the geometrical sections of Elements were actually rearrangements of Exodus previous work. However Euclid himself is said to have made several discoveries in his Number Theory, which is a branch of mathematics that deals with the properties and relationships of numbers.
Most historians believe Euclid was educated at Athens. His teachers may have included pupils of Plato, who was a philosopher and one of the most influential thinkers in Western philosophy. Euclid thought geometry in Alexandria and opened a school of mathematics there. He also wrote Data, which was a collection of geometrical theorems; Phenomena, a description of the heavens; and The Division of the Scale, which is a mathematical discussion of music. But yet again many historians believe many of these works (other than the Elements) were spuriously credited to him, others disagree and say that indeed his works are that of his own.
Euclid's Elements was used as a text for 2000 years, and even today a modified version of its first few books forms the basis of high school instruction in plane geometry. The first printed edition of Euclid's works was a translation from Arabic to