First of all, when you buy a book must have here is primarily electronic-money.
Card handy or afraid.
Once you have subscribed to the e-book site, let you buy a book.
And books purchased will be dedicated Viewer to browse or afraid. To download the viewer can enjoy reading.
Then I actually try it, because it also used the paper is like easier to read. The benefits also. Reading is perfect is unnecessary lighting, so sleep the night before.