John Napier, Scottish mathematician, c 1600s.
© Science Museum / Science & Society Picture Library
John Napier (1550-1617) spent 20 years on the research that would lead to the invention of logarithms: a method of reducing a complex multiplication to that of a simple addition. Napier is probably better known for his comparatively trivial invention of the 'Napier's Rods' or 'Bones' calculating apparatus. He is also thought to have introduced the decimal point into common usage.