Euclid was an ancient Greek mathematician known as the 'Father of Geometry.' His masterwork Elements is the most successful and influential mathematics textbook in history, systematically organizing all known geometric knowledge into an axiomatic deductive system built from self-evident postulates.
Euclid's five postulates remain the foundation of geometry, with the fifth postulate giving birth to non-Euclidean geometry. The axiomatic method he established not only laid the groundwork for all of mathematics but became the model for rigorous scientific thinking, with an influence that endures to this day.