Euclid is one of the most popular mathematicians that have ever existed. He has influenced the world and changed the way we see math for generations to come. Thanks to Euclid we have what is known today as geometry. "He is often referred to as the "father of geometry" due to the concepts he explored in  Elements of Geometry , his most famous and influential wor k ." 1 It has been said that besides for the Bible the "Elements of Geometry" has been the most studied book around the world. Euclid is of the Greek name Εὐκλείδης , which means "renowned, glorious" 2
Biography
Very little is known about Euclid's personal life. It is believed he was born 365 B.C in Alexandria, Egypt and studied in Plato's School of Athens, where most of the most famous philosophers came from. It is also believed that Euclid founded the Ale xandrian School of Mathematics. Euclid was known to be a person of good character. A historian called Pappus stated "that Euclid was: " most fair and well disposed towards all who were able in any measure to advance mathematics, careful in no way to give offence, and although an exact scholar not vaunting himself." 3 Although very little is known for certain about Euclid's personal life what we do know is he was very influential. His textbook is one of the most widely published books in the world. Euclid also funded schools and taught students while he was in Alexandria. His textbook "the elements" was offered as the main textbook for teaching math to students around the world. Euclid's textbook was mainly based on geometry.
Major Works
Euclid's most important work is a book called "The Elements". The Elements is separated into 13 books. Each b ook teaches a part of geometry:
Book 1 contains 5 postulates and 5 common notions, and covers important topics of plane geometry such as the  Pythagorean theorem , equality of angles and  areas , parallelism, the sum of the angles in a triangle, and the construction of various geometric figures.
Book 2 contains a number of topics such as the equality of rectangles and squares, and concludes with a construction of the  golden ratio .
Book 3 deals with circles and their properties.
Book 4 constructs the  HYPERLINK "https://en.wikipedia.org/wiki/Incircle" \o "Incircle" in circle  and  circumcircle  of a triangle, as well as  regular polygons  with 4, 5, 6, and 15 sides.
Book 5, is on proportions of  magnitudes .
Book 6 applies proportions to plane geometry
Book 7 deals with elementary number theory .
Book 8 deals with the construction and existence of  geometric sequences  of integers.
Book 9 applies the results of the preceding two books and the construction of even  perfect numbers .
Book 10 proves the irrationality of the square roots of non-square integers
Book 11 generalizes the results of book 6 to solid figures: perpendicularity, parallelism, volumes and similarity of  parallelepipeds .
Book 12 studies the volumes of  cones ,  pyramids , and  cylinders .
Book 13 constructs the five regular  Platonic solids  inscribed in a sphere and compares the ratios of their edges to the radius of the sphere.
There is no original copy of "The Elements " existing, i n this book Euclid didn't write an introduction, no examples, only theorems and their proofs. "Most of the theorems appearing in the Elements were not discovered by Euclid himself, but were the work of earlier Greek mathematicians such as Pythagoras (and his school), Hippocrates of Chios, Theaetetus of Athens, and Eudoxus of Cnidos . However, Euclid is generally credited with arranging these theorems in a logical manner." 4 Euclid was very important and influenced people like Abraham Lincoln, Issac Newton, Galileo Galeli , etc.

In conclusion, Euclid was a very influential man. He influenced Einstein who considered "The Elements" a "holy little geometry book". 5 He influenced Abraham Lincoln who carried a copy of Euclid's book in his saddlebag and Euclid's book had an impact on many other important people. Historians still try to learn more about his life and try to better understand all the work he left behind fo r us to use. Euclid was a great mathematician who changed