I believe it is best to know what strategies are being employed so that you can be more fully aware of a written work's structure.
-- David Foster (Chapter 1: "The Structure of Nonfiction Information")

Importance: Foster here explains why he asks his readers to think as writers: by imagining themselves as writers and the choices they thus have to make regarding structure, the reader becomes familiar with what to expect in a given genre of nonfiction work. Thinking as a writer acts almost as a 'cheat' for learning to read critically and interrogatively.

The writer of a prologue is under twin obligations, first to write something that will entice and tantalize, and second to make sure the rest of the book lives up to the promissory note that draws us in. In exchange, readers are under an obligation to give that prologue the attention it deserves.
-- David Foster (Chapter 3: "The Power of the Prologue")

Importance: Foster here encourages the reader to take prefatory material such as the prologue seriously...