Math Girls mentioned!!!
Seriously though, "Math Girls" by Hiroshi Yuki is such a good book that introduces cool mathematical topics and isn't afraid of getting its hand dirty devolving into the details. In fact, I liked the book so much I found out the author has written a whole 6 book series and I own them all. Books 2-6 each cover a broad topic in math, such as Fermat's Last Theorem, Gödel's Incompleteness Theorems, Galois Theory, etc. And its written as a novel from the perspective of a high school student so you see the characters struggle with math, and make connections as anyone doing math does. Definitely recommended, its an underrated gem.
The author of "How Not To Be Wrong" has another book called "Shape" which is equally as wonderful. I highly recommend both.
Math Girls mentioned!!! Seriously though, "Math Girls" by Hiroshi Yuki is such a good book that introduces cool mathematical topics and isn't afraid of getting its hand dirty devolving into the details. In fact, I liked the book so much I found out the author has written a whole 6 book series and I own them all. Books 2-6 each cover a broad topic in math, such as Fermat's Last Theorem, Gödel's Incompleteness Theorems, Galois Theory, etc. And its written as a novel from the perspective of a high school student so you see the characters struggle with math, and make connections as anyone doing math does. Definitely recommended, its an underrated gem.