> The slide rules, also known colloquially as “slip sticks”, were the only calculators available before the electronic age, traveled with the Apollo 11 on the M

> The slide rules, also known colloquially as “slip sticks”, were the only calculators available before the electronic age, traveled with the Apollo 11 on the Moon and, essentials on board aircraft for the dead reckoning, are still required as a means of emergency. This sentence is funny for several reasons, not least of which is it comes after a long list of pre-electronics calculators. The mention of dead reckoning totally reminded me of one of the coolest math books I ever bought, and I think I first heard about it in a comment here on HN. Maybe I can pass this recommend on to someone else who will appreciate it. “Dead Reckoning: Calculating Without Instruments” by Ronald Doerfler https://www.amazon.com/Dead-Reckoning-Calculating-Without-Instruments/dp/0884150879 https://www.amazon.com/Dead-Reckoning-Calculating-Without-In... It covers how to do lots of calculations very efficiently mentally or manually on paper, not just arithmetic but roots and powers, logarithms and exponents, and trig functions (sin,cos,tan,asin,acos,atan). Lots of interesting number theory, lots of stuff that’s useful in computer science, and a tour de force of the most important analog calculator this article didn’t cover: the human calculator. ;)