Amazon began selling hardcover and paperback books in July
1995. Twelve years later in November 2007, Amazon introduced the
revolutionary Kindle and began selling Kindle books. By July 2010,
Kindle book sales had surpassed hardcover book sales, and six months
later, Kindle books overtook paperback books to become the most popular
format on Amazon.com. Today, less than four years after introducing
Kindle books, Amazon.com customers are now purchasing more Kindle books
than all print books – hardcover and paperback – combined.