Wow! - what a wonderful example of how tutorials and documentation should be written. Absolutely facinating reading. Some of the clearest concept explanation I have ever seen.

It introduces so many new ideas so simply and clearly, and, best of all, incrementally and gently, all with a subtle sense of humor.

Hmm - I'd better sign off - I'm beginning to sound like a sales-droid (I am NOT one), but this certainly classfies as some of the best technical writing I have ever seen.