Q: I have bought a book on iBooks using my iPad but I can’t get the book to appear in the iBooks app on my iPhone. If you buy a book on one device can you not read it on another even if they are using the same iTunes account on the same PC?
A: Books purchased through the iBookstore on one device are not automatically downloaded by the other device directly over the air. Instead you must either sync them via iTunes on your computer or re-download them manually from the iBookstore “Purchases” screen.
Books purchased from the iBookstore on your device are automatically transferred back to iTunes during the next sync provided your computer has been authorized for the iTunes Store account used to purchase those books. To manually authorize your computer for your iTunes Store account, simply choose Authorize Computer from the Store menu in iTunes and enter your username and password when prompted.
Once transferred, these books become available for syncing to other iOS devices via the “Books” tab in the iTunes Device settings.
If you have the “Sync Books” setting enabled for your device in iTunes, any new books transferred in from other device will be automatically selected for synchronization, regardless of whether you are syncing “All Books” or “Selected Books.” This means that as long as you have syncing of books enabled for your iPhone any books you’ve purchased on your iPad should automatically end up on your iPhone once you’ve synced both devices with iTunes. If the “Sync Books” option is not enabled for your iPhone, you can simply enable it from here, choose to select all books in your library or only selected books and then select the title(s) you would like to sync with your device.
Alternatively, all of your purchased books appear in the iBookstore on your device under the “Purchases” tab.