For three centuries the slide rule was how the world’s engineers actually computed, and Instruction for Using a Slide Rule is the plain manual of its craft: setting the scales for multiplication and division, reading squares, cubes and roots, and keeping track of the decimal point — the one thing the rule never did for you.
Bridges, aircraft and the early space programme were all figured on instruments like this. Download the free EPUB and learn to drive the machine that ran the analog age.