To backup your books:
1. Connect your device to a computer that has iTunes installed
2. Open up iTunes on your computer
3. In iTunes, click on your device
4. Now click on "Apps"
5. Scroll down until you see ReadMe! in the list, click on that
6. On the right side in iTunes, you should see a folder called "epubs", select this folder and drag it unto your desktop.
7. Wait for the copying to finish