"Harry Potter and the Cursed Child" came out to much fanfare over the weekend, and the world is now divided into two groups: those who have finished reading it and those who have not.
But there was no shortage of emotion from both sides.
The book comes from the script for a West End play based on an original story by J.K. Rowling, Jack Thorne and John Tiffany and written by Thorne.
But anything Harry Potter is magical -- especially for fans who got their last literary fix with "Harry Potter and the Deathly Hallows" in July 2007.
"LOOK HOW HAPPY I AM," tweeted one person along with photos of herself clutching a copy of the book.
As with any cultural phenomena in the social media age, there has been plenty of fawning, dissing and irritation about spoilers.
Critics weren't as swept away by the latest project.
"The big problem is 'The Cursed Child' is less an original story than a remix of the existing Potter mythology," Andy Lewis wrote in The Hollywood Reporter.
"The been there, done that feeling to the whole thing is its greatest weakness."
Jessica Contera of The Washington Post
noted that while the play may work, the publication "as a mere script, where everything besides dialogue is written as bland stage commands ("Albus is sleeping in a pew. Ginny is watching him carefully. Harry is looking out the opposite window"), it feels nothing like the detailed-filled paragraphs of the Rowling we love.
"It's more like sneaking a peek at her unfinished notes or finding a fetching piece of fan fiction," she said. "The magic is stunted."
One of the biggest complaints from fans appears to be not what is in the book but rather what isn't.
Teddy Lupin, Potter's godson and the son of Remus Lupin and Nymphadora Tonks, does not make an appearance.
Teddy was part of the "Nineteen Years Later" epilogue in the final chapter of "Harry Potter and the Deathly Hallows," which also serves as the kickoff for the new book. There has been some chatter about his disappearing act in "Cursed Child."
One reader simply tweeted, "where's teddy tho #CursedChild."