Visual Books that can be perused:
These are texts (serious, but highschool accessible). But still good inclusion because they have lots of lovely pictures! They’re the sort of book you can just flip through, see some neat stuff, and get a sense of what future maths can looks like (since they start at, but go beyond elementary maths)
An Illustrated Theory of Numbers
Pop Math Books:
Music by the Numbers: From Pythagoras to Schoenberg <— fun book on music and math; short, nicely chunked
Zero: The Biography of a Dangerous Idea <— I think this is the zero book I read back when I was a freshman and quite liked. Regardless, I’m confident that it’s good. :)
Chaos: Making a New Science <— I haven’t read this, it’s just a very popular pop math book that a lot of people have liked so seems fitting 🤷♂️
Puzzle Books:
The Green-Eyed Dragons and Other Mathematical Monsters <— book filled with math puzzles. Again, nice because you don’t need to read the whole thing. It’s interesting even if you just read one page. Some of the puzzles are very difficult to understand (e.g. the eponymous green eyed dragons puzzle); they’re designed to be the sort that you ponder over weeks / months. They’re meant to exhibit solutions that challenge intuition.
Historical / Visual Arcana:
Oliver Byrne’s First Six Books of Euclid (one book)
^ this books is a rendition of Euclid’s Elements but with the proofs rendered almost entirely visually in a style very reminiscent of De Stijl. This may or may not tickle your fancy if you’re trying for an emphatically ‘anti-dusty’ swagger to math for your students. But it is a breathtaking bit of history rendered in a clever style. And may stoke some students imagination as a little puzzle just to decode how it’s written and then look at some of the proofs. Also an interesting talking point (re: advanced approach to proof based mathematics appearing so early and suddenly in history.)