5Read is also a choice if you are viewing item details. Navigate to the item, tap Item details & options, and then tap Read.
To buy a copy of a borrowed eBook from your library:
1On the Home menu, tap my library.
2Navigate to the borrowed eBook that you want to buy.
3Tap Select. Your NOOK displays a detail page for the item that includes pricing information.
4Tap Buy for $amount.
5Tap Purchase Now to confirm your purchase. The item is immediately delivered to your online digital library and downloaded to your NOOK.
To buy a copy of a borrowed eBook while reading it:
1Tap Buy. Your NOOK displays a detail page for the item that includes pricing information.
2Tap Buy for $amount.
3Tap Purchase Now to confirm your purchase. The item is immediately delivered to your online digital library and downloaded to your NOOK.
Delivery and Download
When you accept a lending offer, the eBook is delivered to your online digital library and automatically downloaded to your NOOK.
Borrowed Indicator
When someone has lent you a book, it is in your library. It has a 
indicator next to it.
Returning a Borrowed eBook
An eBook that is lent to you is returned automatically after 14 days (at the beginning of the 15th calendar day).
NOOK User Guide | Lending eBooks | 136 |