What light switches and GPs are for Muggles, Deluminators and the Marauder’s Map are for the wizarding world.

Portraits that converse, papers that stack themselves, and traveling through fireplaces is a part of everyday life. The magical illusions performed in the course of the story of Harry Potter and the Cursed Child needed to be organic to that culture.

“The nature of this show is that it starts with a line of suitcases and the suitcases became a train carriage,” says illusion designer Jamie Harrison. “Staircases become bookcases. Arches become forests. The world of magic that we were to create needed to be a part of that world, to feel natural and human and handmade.”

Several years earlier, Harrison was invited to be a magic consultant on a production John Tiffany was directing at the West Yorkshire Playhouse. The director had seen his work with Vox Motus, a Scottish theater company Harrison cofounded, which uses elements of illusion, puppetry, and magic effects in their productions.

“They’re not an add-on of wheeling a box onstage and suddenly we do a trick,” he explains. “What we do is create theater that uses magic as narrative.” Harrison worked again with Tiffany on Peter Pan at the National Theatre of Scotland, and when he heard rumors about Tiffany and a Harry Potter show, he was happy, scared, and amazed when Tiffany called him.

“The opportunity to be the guy who did the magic for Harry Potter? I literally went home and went through the books. Then the worry crept in—what’s he going to ask me to do?” Harrison decided that he was not going to hold back anything for fear of failure. “I said to myself, ‘You’re going to have to be really brave on this project because if we play it safe on Harry Potter, we’re never going to make anything different, we’re never going to do anything new.’ We needed to do things that could excite and create something special.” And Harrison did not want to let the fans down. As they began workshops for the show, Harrison brought on Chris Fisher as illusions associate. Harrison met Fisher during the illusions workshops for Charlie and the Chocolate Factory and discovered they had a similar background in magic. “In terms of our job, you can’t get much bigger than being asked to do magic for Harry Potter!” Fisher says. “You literally don’t get a lot of opportunities like that.”

The magic of Harry Potter and the Cursed Child is intricately intertwined with all other departments, and worked specially closely with movement director Steven Hoggett, who always reviewed what the actors were doing during an illusion. “Some of our illusions are really physical,” says Fisher. “You wouldn’t believe the stretching of the legs, all the contorting of the bodies. Because of his warm-ups, Steven gets the performers ready to do what they need to do.” Harrison explains, “For our illusions, actors would often have to do something that would look contrived if it was realized that they were about to do a trick. Steven helped normalize and naturalize these difficult moments.” Collaborations were also key with the other creative teams. “For example, there are specific moments in the show where the costume is vital, but the audience doesn’t know this,” Harrison explains.

“Characters can’t suddenly come on wearing a special costume that looks completely out of sync with others in the scene. In order to have that one moment work, we need to feed this costume idea through the whole show.” Often, dozens of prototypes and hours of discussion would pass between Harrison and Katrina Lindsay, or Harrison and Neil Austin or Gary Beestone until a resolution would be found. “There were times when you’re thinking, ‘I’m never going to make this work,’” says Harrison. “And it would be those times that Katrina or Neil or Gary would say, ‘Come on, we’re going to get this.’ We all knew that we needed to help each other.” From Polyjuice Potion to Pepper Imps telephone boxes to the Floo Network, representing the magic of Harry Potter’s world was a collaborative effort.

Spells and wandwork were no exception. While the script for Harry Potter and the Cursed Child was being written, production assistant Imogen Clare- Wood was asked to make a list of every spell that was used in the play and a description from the books of what each spell looked like. Jack Thorne looked to her for further specifics. “I remember Jack asking if I could give him a list of spells that would be used in a duel,” says Clare-Wood.

“What they do and what they are so he could figure out what to put in the duel between Harry and Draco.” Thorne used what was possible but also added to the inventory of wizard spells; for example, Fulgari, where a wizard’s wrists are bound by vicious, luminous cuffs, and Molliare, the cushioning charm Albus and Scorpius use when they leap off the Hogwarts Express. These were developed by Thorne, then named by Rowling. “I always tried to name them,” says Thorne with a smile, “but she always had something better.”

Harry Potter and the Cursed Child: The Journey, by Jody Revenson, publishes today in the UK and 5 November, 2019 in the US.

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