First draft of template engine chapter

I've added myself to the table of contributors, but I have a few questions about the information we're choosing to present.
To continue on my previous comment, I think that this sentence is the hook into your entire chapter. When you're focused on generating documents with dynamic content, it's easier to think in terms of documents than it is to think in terms of the code that generates them. So, what if we invert the relationship between the document and the program?

In my opinion, the earlier we can present this idea, the better.