John Napier (mathematician) (1550-1617), Scottish mathematician, born in Merchiston Castle in Edinburgh, and educated at the University of Saint Andrews. He became an adherent of the Reformation movement in Scotland while still at college, and in later years he took an active part in Protestant political affairs. He was the author of A Plaine Discovery of the Whole Revelation of Saint John (1593), the first important Scottish interpretation of the Bible.

Napier is best known as the inventor of the first system of logarithms, described in Canonis Descriptio (1614). The common and natural systems of logarithms used today do not employ the same base as Napier's logarithms, although natural logarithms are sometimes called Napierian logarithms. Napier was one of the first, if not the first, to use the decimal point in expressing decimal fractions in a systematic way and according to the modern system of decimal notation. He also invented mechanical systems for performing arithmetical computations, described in Rabdologia (1617).