Even as Harry Potter author JK Rowling proclaims that saying goodbye to Harry Potter was as hard as she always thought it would be, retailers are preparing to give the boy wizard a record setting send off.

Even while I'm mourning, though, I feel an incredible sense of achievement, Rowling said on her web site Tuesday. I can hardly believe that I've finally written the ending I've been planning for so many years.

The seventh and last book of the Potter series, called Harry Potter and the Deathly Hallows, will be released on July 21 later this year and is expected to quickly become one of the fastest selling, if not the fastest selling book of all time.

Booksellers such as Barnes & Noble (NYSE: BKS), and Amazon.com (NASDAQ: AMZN) and Borders (NYSE: BGP) are actively promoting the title on their websites, and are already doing record business with pre-order sales. Amazon recently announced that its first day of pre-orders was 500 percent higher than that for the sixth book released in 2005.

Scholastic (NASDAQ: SCHL) Potter's american publisher, has set the retail price for the book at $34.99, but stores, offline and online, will carry the book at steep discounts.

Although a small revenue source for publishers, an e-book version of the last Potter tale won't be available for download. Rowling said according to a report this week that that there continue to be no plans for releasing the book in that format out of concern for online piracy and her wish for readers to experince the book version of the story.

Since the series began nearly 10 years ago, more than 325 million copies of the book have been sold in 64 language around the world, according to the book's UK publisher, Bloomsbury.