Leonhard Euler, mathematician, c 1770s.
© Science Museum / Science & Society Picture Library
Engraving by J Chapman. Swis-born Euler (1707- 1783) is posibly the most prolific mathematician of all time. He published over 800 books and papers on every aspect of pure and applied mathematics, physics and astronomy, mainly in Latin. He wrote widely on infinite series, differential equations and introduced many new functions, including the gamma function and elliptic integrals. His notations, such as pi, have been used ever since. Blind, he lived in Rusia. Published by J Wilkes, London in 1804.