‘Harry Potter’ is back

On Saturday night, bookstores across the country will do something they haven't done in a long while: Fling open their doors to host late-night parties for masses of Muggles looking to get their Harry Potter fix.

The last time booksellers were revving the hype machine for a new title in J.K. Rowling's wizarding series, the year was 2007, for the last book in the series. Borders still existed. So did Waldenbooks and B. Dalton.

Amazon was months away from releasing the first Kindle e-reader.

Now, even as the business has changed dramatically, the splashy sales expectations for Harry and friends have not: Barnes & Noble and Amazon both say that 'Harry Potter and the Cursed Child” is their most pre-ordered book since the last Potter installment, and Barnes & Noble projects it will be the chain's biggest-selling title of the year.

Scholastic, the book's publisher in the U.S. market, is expecting double-digit growth in its trade-publishing division in the next year, thanks in large part to an anticipated Potter frenzy.

And so retailers big and small are dusting off the sorting hats and the Quidditch brooms this weekend, testing whether the old formula of costume competitions, trivia battles and games like 'pin the nose on Voldemort” can still work in a new shopping moment, one in which even more sales have moved online and when the original cohort of kiddie Potter fans has grown up.

At Barnes & Noble, executives plan to lean into the idea that the Harry Potter fan base is perhaps more multigenerational than it was the last time around, as the original millennial Potter readers are now in their 20s.

'Back in 2007, the sweet spot of our events was really focused on the eight-to-10-year-old,” said Mary Amicucci, chief merchandising officer at Barnes & Noble. 'Now we're going to have something of readers of all ages.”

For example, during the launch parties, instead of just doing child-friendly craft activities such as wand-making, Barnes & Noble will be tricking out its stores with a Muggle Wall where longtime readers can scrawl their favorite memories of the series. ('Muggles” is the Potter-world term for us ordinary humans who do not have magical powers.)

There's plenty of reason beyond the strong pre-order numbers to believe that Barnes & Noble and other retailers will have a hit on their hands with 'The Cursed Child” - Harry Potter has remained close to the pop culture epicenter thanks to hit movie versions of the books and the debut of the Wizarding World of Harry Potter theme parks at Universal Studios.

And yet it remains to be seen how Potter loyalists will react to the format of this book, which does not fit the mold of the first seven stories. 'The Cursed Child” is written as a play, one that is set to debut onstage this weekend at London's Palace Theatre.

The script is written by Jack Thorne and is based on an original story he developed with Rowling and John Tiffany, although Rowling's byline gets top billing on the book.

And while the rest of the Potter series followed Harry, Hermione and company through their adolescent years at Hogwarts, 'The Cursed Child” is set many years down the road, featuring the original characters as grown-ups sending their own children off to magic school.

Scholastic has printed 4.5 million copies of the book for the North American market this time around, fewer than it printed for the first run of 'Harry Potter and the Deathly Hallows.” But Ellie Berger, president of trade publishing at Scholastic, said this simply reflects a compressed timeline the publisher faced in getting the final version of the script.

Despite the different story structure, Berger said, 'It's the characters we know, who we love. There's a lot of familiar things in this new story. Whatever the format, there's new content, there's new adventure.”

And yet Steven Aarons, owner of independent toy and bookstore Child's Play, said he's expecting that his sales of 'Cursed Child” might reach only 30 to 50 percent of sales of 'Deathly Hallows.” He's not sure the theatrical-play format will have quite the same appeal, and fans are no longer used to the ritual of coming out for a new Harry Potter title roughly every year.