Napier and the Invention of Logarithms

John Napier published his tables of logarithms in 1614. The idea was revolutionary: multiplication becomes addition, division becomes subtraction, powers become multiplication — all via a lookup table. Kepler called Napier's invention 'a stupendous feat of the human mind.' Astronomers had previously spent months on multiplication of 8-digit numbers; with logarithm tables, the same computation took hours. The logarithm reveals something deep: that multiplication and addition are secretly the same operation in different 'worlds.'