With My Book List you can easily synchronize all your books using multiple devices such as an iPhone or iPad. This feature is called Database sync & backup and can be found in Settings → Add-ons. After unlocking it, you will need to authenticate using your Facebook account. Follow the same procedure on all devices, starting from the one that currently has the books saved. Do not worry, Apple knows what you purchase and therefore will only charge you once for an unlimited number of devices. As a bonus, this feature we also keep a backup of your database in the cloud os you can always retrieve it in case your device gets lost.