Leonhard Euler (15 April 1707 – 18 September 1783) was a pioneering Swiss mathematician and physicist.
He made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function.He is also renowned for his work in mechanics, fluid dynamics, optics, and astronomy.
Euler spent most of his adult life in St. Petersburg, Russia, and in Berlin, Prussia. He is considered to be the preeminent mathematician of the 18th century, and one of the greatest mathematicians to have ever lived. He is also one of the most prolific mathematicians ever; his collected works fill 60–80 quarto volumes.
A statement attributed to Pierre-Simon Laplace expresses Euler's influence on mathematics: "Read Euler, read Euler, he is the master of us all.