John Napier was a Scottish mathematician, physicist, and astronomer who lived from 1550 to 1617. He is best known for his invention of logarithms, which greatly simplified complex mathematical calculations. Napier also developed the concept of Napier's bones, a manual calculation device, and made significant contributions to the field of trigonometry. Additionally, he was a pioneer in the use of decimal notation and made important contributions to the understanding of the properties of the circle. Napier's work laid the foundation for many advancements in mathematics and science.