Why do books have chapters? What is the best way to denote those chapters?
Most books have chapters. For non-fiction books, the chapters serve to group the information into topics. The title of the chapter decribes the information given in that chapter. If you pick up a book on knitting and turn to the table of contents(TOC), you can find the chapter on Fair Isle Knitting without having to go through all the chapters on basic knitting techniques. The TOC will tell you that the chapter starts on page 97, so you flip through to page 97. E-books don't have page numbers, but they do have TOCs, and the chapter listings are clickable links. Select and click on Fair Isle Knitting, and there you are.
Fiction books, on the other hand, are meant to be read from front to back -- yet they are usually still grouped into chapters. Not always, of course. Many of Terry Pratchett's books do not have chapters. Moll Flanders, by Danial Defoe, did not have chapters. Most books, however, greet the reader with a large 1 at the beginning of the story, and further numbers occur at regular intervals.
Chapters are an invitation to set down the book, to stop reading. To dissuade this, many authors end their chapters with cliff-hangers that encourage the reader to continue untill, at least, the current crises is solved. And then, of course, the reader thinks to continue to the end of the chapter, but there they find a new cliff-hanger.
So one use of a chapter is to give the reader a false sense that there are stopping places, when in reality there aren't. This is a bit like being told that a rest stop is coming up in 2 miles, only to be informed next that the rest stop is closed and you have to wait 36 miles for the next one. And you wait that 36 miles because you know that the rest stop is coming. When there are no chapter breaks and no assurance than a stopping point is coming, the reader feels welcome to set their bookmark, weel, anywhere.
Chapters have a deeper purpose, however, for the author. Chapters break a long manuscript into managable pieces. It's a lot easier to search 16 or 10 pages at a time for typos and errors, and you feel more compelled to get to the end of a chapter than a long novel. And if the chapters are short, then you can fool yourself with "Just one more," a concept that is making video game developers rich.
The next question, then, is how to name the chapters. Numerically is very common. Not only does this take much less imagination that proper titles, it also helps in the final assembly of the book. If each chapter is a separate computer file, a numerical name keeps them straight. And what reader needs a chapter title when they are busy reading from the last cliffhanger to a new one?
The eBook is about to change this. EBooks need to have TOCs to help the readers page through the books, but as was pointed out to me yesterday, when an eBook has a TOC that consists of only Chapter 1, Chapter 2, Chapter 3, etc., it looks odd. Boring.
Note to self -- in the future, all book chapters should have a number and a title. Just getting ready for the new world, that's all.