Which mathematician is credited with inventing the modern logarithm in 1614?

John Napier is credited with inventing the modern logarithm, which he described in his 1614 work Mirifici Logarithmorum Canonis Descriptio. Logarithms transformed multiplication and division into addition and subtraction, greatly reducing the effort required for astronomical and navigational calculations before electronic calculators.

Napier was a Scottish landowner, mathematician, physicist, and inventor. His original logarithms used a form and scaling different from the common logarithms taught today, and his methods were connected to trigonometric calculations. English mathematician Henry Briggs later visited Napier and helped develop the base-10 logarithms that became especially convenient for practical computation.

Logarithms also underpin the slide-rule tradition and remain important in science. Natural logarithms use the base e, while common logarithms use base 10. Napier should not be confused with Leonhard Euler, who popularized the notation and theory surrounding e, or with the later development of logarithmic scales in fields such as acoustics and seismology.