I don't understand your question are you refering to the content or the actual book?
I'll try to deal with both topics.
I normally write about things I know about, for example I won some years ago, Junior Mr. Lancashire in a bodybuilding competition, so at the age of 17 (before the age of the internet I may add!) I wrote out my training course and got someone to type it up. Ok, so you'll be good at something, are you the guy who does the best BBQs in your area? Does everyone ask you to sort their car out? You get the jist??
Writing an ebook.
I use a free program called openoffice, you can download it free from Link hidden: Login to view
I use the writer and its almost like using Microsoft Word, but when you have finished and checked the document, you click on a button marked PDF and name it, then its saved to your computer as a PDF file!
Done! Then sell it...