So, seeing as this subforum is pretty much entirely composed of (threads about) works of fiction, I'm not sure how well this will fit in, but I think it will at least fit in
relatively better than it would in any of the other subfora:
I'm currently reading, and heavily enjoying,
Homotopy Type Theory: Univalent Foundations of Mathematics. I'm coming at it from a computational/type theory angle, but it's meant for anyone with an interest in foundational and/or abstract math, and generally explains anything that some readers might not know. You can get it as a free PDF or eBook from the linked page, or buy a physical copy if you want. Just reading some of the
Introduction will probably tell you whether the rest of it will interest you or not.