Napier, Albert A.
Although best known for his invention of logarithms his other mathematical contributions include a mnemonic for formulas used in solving spherical triangles, two formulas known as Napier's analogies used in solving spherical triangles and other inventions. He also found exponential expressions for trigonometric functions, and introduced the decimal notation for fractions.
Napier, however, will be remembered for making one of the most important contributions to the advance of knowledge. It was through the use of logarithms that Kepler was able to reduce his observations and make his breakthrough which then in turn underpinned Newton's theory of gravitation.