Edmund Gunter
The slide rule was invented around 1620–1630, shortly after John Napier's publication of the concept of the logarithm. In 1620 Gunter developed his calculating device with a single logarithmic scale. With additional measuring tools it could be used to multiply and divide. In c. 1622, William Oughtred of Cambridge combined two handheld Gunter rules to make a device that is the modern slide rule.