If you take a glance at the linked document, as I just did, it appears to cover the hardware graphics pipeline which is more than just a Cg programming language reference. Cg as a language is more or less the same as any other high level shader language of the same era.

I did look at the linked document and poked around, it was all Cg (the programming language) centric. Which obviously overlaps substantially with computer graphics, but isn't what I'd consider an ideal introduction to the field unless the goal is to work with the Cg language.