Topic: Ruby and Rails bible? (buying 2 books for reference)

Hello everyone!

I'm a rather new user of ruby on rails, I created a few simples apps and read some tutorials and beginner's books.

I would like to buy 1 or 2 books to keep as reference guides (maybe one for Ruby and other for Rails), and to read to try to understand the inner works of Rails and Ruby.

Which book would you recommend? I thought maybe

Re: Ruby and Rails bible? (buying 2 books for reference)

Agile Web Development with Rails (3rd edition)
by Sam Ruby, Dave Thomas, David Heinemeier Hansson