Hypertext Principle #1

You cannot directly convert text to hypertext.

Printed material is the stuff of an industry based on ink and paper.  
Familiar structures - tables on content, indexes, footnotes, and endnotes - are designed for economy of this industry/medium.
How people find their way around a printed work:
"I flip through the pages back-to-front until I see the weather map or the picture of such-and-such. I know it's just past the middle, on the back side of a page."
They are referring to artifacts of the printed work - which may have value as on-line wayfinders.
They define an implicit structure for the user - sometimes referred to as tacit knowledge.
Artifacts help us to fine-tune our knowledge of the global structure to find our way in an instance.
When we analyze entry points we find that they suggest the importance of being able to "see" how much stuff there is, what it's about, and where specific content lies in relation to the whole.
Readers must have artifacts to make inferences analogous to physical size, shape, and dimensions of the printed work.
Donald Norman notes that our information-based technological world has an inherent problem: It is invisible.
"It is up to the conveyor of the information and knowledge to provide shape, substance, and organization...[via artifacts]." Without appropriate design of artifacts in our virtual domains, Norman says, "...our tools will continue to frustrate, to confuse more than clarify, and to get in the way rather than merge with the task. The power of information artifacts is that they provide an unrivaled opportunity to enhance our lives."