Today, Amazon has introduced a lending feature for US customers. Kindle users across the entire range of Kindle apps and devices can now lend each of their purchased books one time only, for a period of 14 days. The borrower doesn't need to own a Kindle and can use Kindle apps for PC, Mac, iPad, iPhone, BlackBerry, and Android devices.
Titles that are eligible for lending, as determined by the publisher or rights holder, will have a message on the product detail page. Scroll down to the "Product Details" section and look for "Lending: Enabled" as shown below:
To lend a book, go to Manage Your Kindle, click the "+" symbol next to a title to reveal all info and options. If lending is enabled, you'll see a Loan this book button, just click the button. You'll be directed to a form where you'll provide the borrower's name, e-mail address and an optional message.
Or, when your logged into Amazon account, looking at the product detail page of a book you've already purchased. If lending for the book is enabled, you'll see a notice: "Loan this book to anyone you choose." Click the Loan this book link. You'll be directed to a form where you'll provide the borrower's name, e-mail address and an optional message.
The recipient has seven days to open the email message and accept your loan. After accepting the loan, you'll have 14 days to enjoy the book until the download ends. After that, the book will be returned to you. Just like a paper book, you can't read your copy while someone else is borrowing it.