There’s no more dreamlike collision of words and art than the Harry Potter series illustrated—it’s been true since Mary GrandPré first drew the characters of J.K. Rowling’s series on the covers and chapter headings of the saga’s original American run, but it’s continued as Harry Potter has found new life in anniversary editions with equally captivating and unexpected artwork from some of the industry’s leading illustrators.

Scholastic brought three of its all-star Potter illustrators together for an unforgettable panel at San Diego Comic-Con on Saturday. Celebrating the 20th anniversary of Harry in the States, the panel united veteran editor Arthur A. Levine and art director David Saylor (two of the main figures responsible for bringing Harry Potter to the U.S. in the first place) as well as three illustrators who have lent their elegant touches to the series: Kazu Kibuishi, the 15th anniversary edition cover artist); Jim Kay, who is currently drawing his way through illustrated editions of the series, most recently Prisoner of Azkaban; and Brian Selznick, the author of The Invention of Hugo Cabret and Wonderstruck, whose 20th anniversary black-and-white Potter covers are now available.

The program was filled with plenty of visual treats for the packed crowd of fans, but here were some of the most arresting revelations from the panelists:

Image zoom Kazu Kibuishi/Scholastic (2)

1. Each cover Kibuishi created for his 15th anniversary artwork went through about 100 variations — evolutions that took dramatic directions, like Chamber of Secrets moving from a horrifying basilisk battle to the “cup of tea” coziness of the Burrow — but it was the Prisoner of Azkaban cover that changed the game for the artist. “This one was the first sketch that David Saylor at Scholastic looked at and asked me if I could do the rest of the covers this way,” said Kibuishi. The evocative cover art in question: Harry casting his Patronus to conquer a Dementor on the waterfront at Hogwarts, an iconic scene in that story about which Kibuishi noted, “There was no other scene I could imagine painting.” The mood and style of the third cover became the basis for the rest of the covers Kibuishi digitally painted for the series.

Image zoom Kazu Kibuishi/Scholastic

2. Kibuishi’s complete box-set art, meanwhile, is loaded with the kind of Easter eggs that aren’t just a clandestine delight for Harry Potter fans, but keep up a tradition that original American illustrator GrandPré began with her cover art, embedding little gems and call-outs to the story inside her wide wraparound pieces. Kibuishi took it a step further and embedded secret appearances from his own world inside Rowling’s, all within the confines of a Hogsmeade-set painting. “I’m actually in there — I didn’t make it into Hogwarts, but I am working at Zonko’s,” Kibuishi pointed out, although you’ll have to pick up the box set in person to see all the details. “David Saylor is actually running the cash register there. And right above us is J.K. Rowling, working on the book. Arthur Levine is holding a book up in one of the windows in the far left, up top, along with his assistant, Cheryl Klein, who helped me a lot with these covers. And my wife is actually walking up towards us, pretty far in the back. She’s there with my assistant Jason, who insisted he was a Gryffindor.”

Image zoom Jim Kay for Bloomsbury Publishing

3. Kay’s journey with Harry Potter is peculiar (but no less astounding), if only because his work on the series is both unprecedented and far from over. Tasked with the adventure of fully illustrating all seven Potter stories, Kay decided that he’d base the imagery of his characters — and in particular, the children — on real people. “Children age through these books by seven years, so I found real children, and I see them every year and see how they’ve grown,” said the artist, although he acknowledged that even real-world inspiration has its limits. “My Dudley Dursley, actually, he was a lovely rotund boy when I met him,” said Kay. “He’s now lost loads of weight.”

Image zoom Jim Kay for Scholastic

4. Kay revealed that he subscribes to no specific style in his many, many, many pictures for his illustrated editions, and the artist relished sharing all sorts of deliriously interesting facts about his work in the first three illustrated books: how he built a scale model of Hogwarts from rubbish paper, clay, wood, and wool in order to light the castle and replicate it on a page; how he accidentally designed the astronomy tower as Wembley Stadium; how his clay model of Dobby melted and was repurposed as the bottom of his clay model of Buckbeak; how his interpretation of Hogwarts is less structurally stable and instead floats on and grows out of trees, utilizing Rowling’s description of the castle as being literally “held up by magic”; and how his portrait of Severus Snape is loaded with symbolism, including scissors representing the spell Sectumsempra, a mole inside a jar representing Snape’s tragic narrative trajectory, and a lily of the valley representing, of course, James.

Just kidding, it represents Lily.

Image zoom Brian Selznick/© 2018 Scholastic

5. Halloween is a monumentally eventful holiday in the Potter series, so why shouldn’t Selznick have gotten his call to work on the series on that very holiday? Immediately during the pitch, the acclaimed illustrator and author saw his vision: a single piece of art that would spread across all seven covers. “I had an image [in my head] of doing all seven covers as a single story that, when you line them up, tell the entire tale of Harry from the time of his birth until the epilogue 18 years later,” Selznick shared. “I knew I wanted something to tie together all seven of the covers, so I just started drawing lines — swirling, swooping lines that would tie them all together — and then I looked at it and I was like, ‘That looks like a snake! Oh my God, that’s perfect!’ So the snake represents evil, it comes in and out of all seven covers, and ultimately is there on the seventh cover, where you see the head of this snake for the first time, vanquished.” A less literal stroke of luck for Selznick: The illustrator began drawing his first Sorcerer’s Stone cover at the same time that he began listening to Jim Dale’s audiobook recording; thirteen 13-hour days later, he said, “I had gotten to the Battle of Hogwarts in the seventh book exactly as I was drawing Harry and Voldemort on the final cover.”

Image zoom Brian Selznick/© 2018 Scholastic (2)

6. Selznick revealed that he too laced loads of Easter eggs into his covers. Harry’s glasses, he noted, were inspired by glasses Selznick wore as an extra in the film adaptation of his book Wonderstruck. His interpretation of Aragog is directly based on a Louise Bourgeois sculpture. Hooded funerary figures in the graveyard film of the movie Hugo inspired Selznick’s Dementors, while his Fleur Delacour is based on Hollywood screen legend Veronica Lake. Dumbledore’s face is a mirror of Michelangelo’s sculpture of Moses, “which seemed appropriate,” he said, and Dolores Umbridge, being the “most horrifying villain,” inspired Selznick to “find someone to pose as the most hated figure in the series. So I asked my husband.”

Image zoom Peter Mountain/Warner Bros.

7. An interesting question arose from the audience, one that inquired of the illustrators whether the established visuals of the film had any sort of influence — welcome or not — on their work. The answer, in short, and surprisingly, is no. Selznick cited Kibuishi’s bold reinvention for Harry’s 15th anniversary as license to eschew the visuals that came before: “The work that Kazu did on his 15th anniversary gave permission for a new way to look at Harry,” he said. “When those came out, I remember being struck by the fact that it was instantly identifiable as the world of Harry Potter, but in a way that I had never seen before. That, in so many ways, said to me [that] it’s possible to have other visions of it. Going to [Universal’s] Harry Potter world and seeing the movies, the work is so profoundly beautiful and complete, so when it was time for me to sit down, I tried to put all of that aside and go back to J.K. Rowling’s words, and what’s there in the language is there in the drawings.”

Image zoom Scholastic

8. When Levine and Saylor joined the panel, the veteran editor and art director shared stories that helped provide light into the way Harry Potter had taken visual form over the years. The first consideration of author Mary GrandPré was, perhaps unexcitingly, based on a simple pluck through an alphabetized filing cabinet, but being reminded of the illustrator’s work caused “this lightbulb to go off” for Saylor: “She had this beautiful luster to her artwork, soft beautiful pastels but also jewel tones that she brought to her artwork, that we really loved.” Levine added that the experiment in cover art that GrandPré, Levine, and Saylor embarked on back in 1998 was, in some ways, uncharted. “When you think back to 21 years ago, a lot of the things we were talking about in terms of conceiving what that book would look like were really unusual for children’s book hardcover,” Levine pointed out. “To have uncoded stock and matte lamination and gold foil? People weren’t really doing that, and those were all these extra things we were doing to make this book special.”