Programming Language References
As programmers, our most important tools are our languages. Programming languages are not only our tools, they are also the medium in which we work. Less obviously, the programming languages we use affect the way we think about problems. You tend to solve problems in the way that is most comfortable in your language of choice.
Your language of choice is an important tool, the medium in which you do your work, and a viewpoint of the world. For that reason, you should know as much as possible about the language. Seeing how others have used the language well (or badly) and learning how others have pushed a language, are both good ways to get better at our craft.