Leonhard Euler

A Swiss mathematician who worked across half the eighteenth century and produced more pages of mathematics than any other person before or since. He named and developed the theory of the number $e\approx 2.71828$, the natural base of exponential growth: the curve whose slope at every point equals its height. He worked for nearly two decades after going blind, dictating his work to his sons. His identity $e^{i\pi }+1=0$ is sometimes called the most beautiful equation in mathematics.