I'm a fairly new programmer and currently learning ruby on rails with the intention of developing a web application.

I am currently going reading Agile Web Development with Rails 4th Edition and its working well for me, however I'm wondering if somebody can recommend a more general, almost classic book to read casually alongside to help cement the fundamentals in place.

As I said, I'm for the most part a beginner and the only education I've had is this and briefly one other technical book, so I'm sure there must be some "must reads" out there that give me a more substantial context for the basics of either Ruby on Rails, Ruby, objective oriented programming, or programming in general.

What books helped you grasp a deeper and more rounded understanding of your skills as a programmer?

All suggestions are welcome and appreciated.