leenia -

Some of the uses of fields are closely akin to what are called "tags" and/or "links" in other page layout and word processing programs, so they're not exactly "foreign" or particularly arcane to those who've worked with documents professionally, or who've been raised on other kinds of programs. Most people find them naturally when they look up how to do things like making tables of contents, indexes, or to do special formatting.

They provide a reasonably simple way to insert something that changes it's appearance in response to what you type elsewhere in the document. Used for "tagging," you can, for example, mark chapter titles and collect them "automagically" so that they'll appear properly in a table of contents, with correct page numbering etc. "Bookmarks" and "links" to/between them work a lot like html in Word, but you don't have to write the code for them in Word.

Mostly very routine stuff.

John