String, Straight-Edge, and Shadow
An excellent, interesting story of the earliest scientists, from unnamed Egyptians through Euclid, and their ability to figure out basic math using only the three items in the title. How Pythagoras proved his famous theorem (it will blow your mind!), plus the discovery of the Golden Mean by Eudoxus: absolutely incredible. And how Eratosthenes was able to figure out the size of the earth! These people didn't have digit symbols! Unbelievable! Prepare to be amazed.