I think people have a tendency to recommend books relating to things that are currently important to them, like math, programming, technology. While I wouldn't

I think people have a tendency to recommend books relating to things that are currently important to them, like math, programming, technology. While I wouldn't shy away from these, my first inclination would be to recommend books that will influence positive personal growth. There is no guarantee that any particular topic will be crucial in 10 years. I can't recommend a specific book in these categories (since I have learned mostly independently), but I would look for good books which cover: Music Appreciation and low-level Theory, Philosophy (especially Eastern), and Argumentation and Logic.