I just finished sitepoint's book on Rails. It is terrific, and for most part, I understood the material. I just began as an experiment (I've worked with PHP/Java) but now I really like Rails, and would like to get proficient in it.

Any advice on what book to pick up next? I just don't want to learn the syntax alone, I'd like to know some theory (at least the basics) of how things work. I googled around, there is so much material that I feel overwhelmed. If someone would like to share how they learned rails, what books were helpful (especially when they started out) it would be great.