Leonhard Euler Leonhard Euler, (born April 15, 1707, died Sept. 18, 1783), was the most prolific mathematician in history. His 866 books and articles represent about one third of the entire body of research on mathematics, theoretical physics, and engineering mechanics published between 1726 and 1800. In pure mathematics, he integrated Leibniz's differential calculus and Newton's method of fluxions into mathematical analysis; refined the notion of a function; made common many mathematical notations, including e, i, the pi symbol, and the sigma symbol; and laid the foundation for the theory of special functions, introducing the beta and gamma transcendal functions. He also worked on the ori