Amazon's Prime Lending system works by allowing Amazon Prime account holders that own Kindles to borrow and read books from Amazon's Lending Library. As of 2015, the Amazon Lending Library contains over 800,000 unique book titles, including books that are and were best-sellers.
Amazon Prime account holders are allowed to borrow a maximum of one book in each calendar month from the Amazon Lending Library. Once a book has been borrowed, it immediately becomes readable on the Kindle device that is registered to the borrowing Amazon account. Amazon states that the titles available for its Lending Library may change from month to month.
Once the allotted quota of one book has been reached, an Amazon Prime account holder is no longer able to borrow a book from the library. Accounts that are cancelled while a book is on loan immediately lose access to it. Books borrowed from the Lending Library can also be returned at any point in time as there are no due dates associated with the loans.
Amazon Prime account holders can also place highlights, notes or bookmarks in a borrowed book. This data is stored with the account and can be seen again if the book is borrowed or purchased in the future.