What are your favorite books on general CS concepts/theory?

Hello.

I started my first job about 3 weeks ago and I moved cities, so for a while I’m gonna have a lot of free time at night to do what I want.

I like to read a lot and although it’s usually limited to fantasy/sci-fi, I feel like I should try to read some books on concepts and theories.

Ideally they’d be books that don’t require practical work, and aren’t necessarily tied to a specific language.
Does anyone have any good recommendations for books like that?

Thanks!