Usually if you walk into the Brattle with an introductory math textbook you’ll receive a polite ‘no thank you.’ However, it’s a slightly different story when that textbook was published in 1695. In today’s episode, we’re looking at a still-pretty-accurate antique trigonometry book, written in Italian and complete with engraved illustrations and folding diagrams. We’ll talk about what makes technical volumes valuable—aside from sheer age—and why Brattle is less math-phobic than most secondhand book shops (an academia-rich location, strong employees, and Ken’s background in chemistry play a part). Learn how it all adds up on today’s tangential #brattlecast.