‘Harry Potter and the Cursed Child’ goes on sale Saturday night. Here’s what you need to know.

Fans have waited nine long years since the last installment of the magical “Harry Potter” book series came out — but as the clock ticks past midnight Saturday into Sunday, readers can once again immerse themselves in the world that is Harry Potter.

“Harry Potter and the Cursed Child” is the book edition of the play — now on stage in London — by Jack Thorne based on a new story by Thorne, John Tiffany and, of course, Potter creator J.K. Rowling. Harry now works at the Ministry of Magic and is married with three children. His son, Albus, has trouble coping with such a family legacy, according to the play’s website. (Rowling has asked those seeing previews of the play to resist sharing spoilers).

Los Angeles booksellers cannot release the book until 12:01 a.m. on July 31, but that is not stopping them or fans from celebrating in advance all over the Southland.

In Los Angeles, the Harry Potter fan group Dumbledore’s Army is meeting at 5 p.m. Saturday at “King’s Cross Station” (actually Union Station) before singing the Hogwarts House song aboard the “Hogwarts Express” (the Metro Red Line) on their way to “the Leaky Cauldron” (1939 Public House in Los Feliz), where they will have “Harry Potter”-themed cocktails, said Adrienne Alwag-Aipia, who runs the group.

Dumbledore’s Army will be drinking the butterbeer (whatever’s on tap) just down the way from Skylight Books, where the group will head for the release party that starts at 10 p.m. and includes a costume contest, face painting, a photo booth, food, dueling Trivial Pursuit games and giveaways of “Harry Potter” tattoos and pins.

A completely kid-oriented release party is taking place at Once Upon a Time in Montrose. Festivities will include potion-making, a costume contest, a Harry Potter birthday cake to celebrate Harry’s birthday, photo booth, musical chairs, “pin the glasses on Harry” and trivia events, some of which will be easy and some that will be for the “die-hard,” owner Maureen Palacious said. The bookstore will also host a scavenger hunt that will lead to the elusive Moaning Myrtle hangout. And, of course, everyone will be separated into their proper houses. The party begins at 10:30 p.m. Saturday at the bookstore.

Vroman’s Bookstore has partnered with Gallery Nucleus, an Alhambra art gallery, for its event. In addition to another costume contest and photo booth, Vroman’s and Gallery Nucleus will have a wall where partygoers can write what “Harry Potter” means to them, themed food and drinks such as pretzel magic wands and butterbeer and “Harry Potter”-themed art. “In the past, they had a ‘Harry Potter’ art show. We all remember it with fondness,” said Allison Hill, president and chief executive of Vroman’s.

To attend, fans must pre-order a book from Vroman’s. Everyone is allowed one guest, and the party begins 9 p.m. Saturday at Gallery Nucleus, 210 E. Main St. in Alhambra.

On Monday, Barnes & Noble announced that “Harry Potter and the Cursed Child” is the national chain’s most pre-ordered title since the last Harry Potter book, and that it expects it will be the biggest-selling book of the year. Barnes and Noble locations across the Southland will be having parties, too. Check our map for the location closest to you.

Email: Alex.Golden@latimes.com

Twitter:@alexgoldennews

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