Thanks! I read through a bunch of that textbook when I first decided to learn more maths a few years ago, but I relatively quickly started dual-reading a differ

Thanks! I read through a bunch of that textbook when I first decided to learn more maths a few years ago, but I relatively quickly started dual-reading a different textbook ("Introduction to Set Theory" by Hrbacek and Jeck), which is a more in-depth, non-naive introduction. That's the book I'm continuing to work through now.