Bonus: Napier's bones
Forty years is the blink of an eye to the granddaddy of handheld computing: Napier's bones. Developed in 1617 by John Napier, the Bones were ten rods of wood, bone or ivory with a matrix of numbers carved into them, slotted neatly into a handheld frame. By rotating the rods, pioneering geeks performed multiplication, division and even the extraction of square roots.
True, slide rules and log tables overtook the Bones within a few years, but Napier's mighty rods of math were the first and the coolest by far.
Matt Lake is a nonfiction writer and technical services coordinator. He first reverse-engineered a calculation to get the result .07734 in the 1970s, and he's not looked back since.