If you are an e-book publisher then you will probably be producing your books in pdf format so that they can be read on Adobe’s acrobat reader. That’s a good choice – nearly everybody who reads e-books has a copy of the Acrobat reader, and if they don’t they can get it for free. However, it might be worth your time (and it won’t take much time) to also publish a Kindle edition suitable for use with the amazon kindle e-book reader, which is very popular right now. As long as you have a free Amazon account you can upload your books (using Microsoft Word). You choose the price – as long as this is below $10, Amazon will give the publisher (you) 70% of any sales – minus a small delivery fee, which is usually less than $0.15.