A group of bestselling children’s authors gathered for a panel on June 2 at BookExpo, in which they discussed the process of adapting their books to film. The featured writers were Stephen Chbosky, author and screenwriter of The Perks of Being a Wallflower; R.J. Palacio, author of Wonder; and Nicola Yoon, author of Everything, Everything, which hit theaters on May 19. Isabella Biedenharn, assistant editor at Entertainment Weekly, moderated the discussion.

Biedenharn began by asking the authors how they felt when they first learned their work would be translated from page to screen, and if there was any hesitation on their part. Yoon said she was all in from the get-go. “There was a lot of champagne that day. It felt great.” Palacio was initially more anxious. “I was really nervous at first. I wasn’t sure how [the filmmakers] would do it,” she said. But after meeting with several producers and hearing their pitches, she warmed to the idea. “I knew I found the right people, with the right sensibility and point of view,” she said. The team hired Chbosky as director and co-screenwriter four years into the project.

Chbosky had a somewhat different experience as the screenwriter for his own novel in 2012, saying, “I trusted myself to do it.” He believes that the first step in making a successful adaptation is “find[ing] like-minded people who love your book.”

The authors had varying degrees of involvement throughout the adaptation process. Film rights to Wonder were sold in 2012 just after the novel came out, and Palacio said she had “meaningful consult” on the project. She was grateful to have a say in details both large and small, from character development to the hospital settings where protagonist Auggie is admitted. Ultimately, Palacio was willing to hand over the reins to the filmmakers. “Letting go was the greatest challenge and the greatest joy,” she said.

For his part, Chbosky valued Palacio’s feedback on many aspects of filming Wonder. “The author is one of the stars,” he said. Most of his work in transferring Palacio’s narrative to film was in the name of brevity and clarity, such as adding a shot of Auggie being pelted with dodgeballs at recess to convey the boy’s difficult adjustment to school life. Above all, Chbosky was eager to honor Palacio’s story. “Without the author, there is no world. Of course I’d respect that,” he said.

Yoon was also involved in the production process. A 30-minute coffee meeting with director Stella Meghie turned into “a three-hour mind meld” when the two connected over their vision for the movie. Yoon was pleased to learn that Meghie shared her concerns for translating the drawings and other non-traditional aspects of her work to the screen. She gave notes on the first version of the script for Everything, Everything, and even had a brief cameo along with her family during a pivotal scene at the beach.

The authors also had a voice in casting decisions, and were pleased with the outcomes. Chbosky stressed the importance of finding the right actor to bring a character to life. “If you get the wrong person to play the wrong part, it can seriously hurt the film,” he said. Yoon “lobbied hard” for Amandla Stenberg to take on the role of Maddie. When she met actor Nick Robinson, she knew he was right for the part of Ollie. “I thought he was the cutest thing in the world,” she said. Palacio was immediately on board with the casting for Wonder. “If Julia Roberts says she wants to be in your movie, it’s a done deal.”

When it came to individual performances, the writers took a step back and trusted the actors, providing context when needed. Chbosky created a document for the actors with background information on the Kelmeckis family for The Perks of Being a Wallflower. He asked Palacio to provide a similar character map for Wonder. Yoon found it “hard to let go of [her] characters at first,” but knew that the actors would deliver. “They didn’t need me. They had it,” she said. She believes that Meghie and the cast of Everything, Everything did a faithful job in retelling her story of “a girl falling in love with herself, a boy, and the world.” She said of the overall adaptation, “It’s lovely to watch someone else’s art add to mine.”

As newcomers to the film world, both Palacio and Yoon had their share of surprises. Palacio considers herself “a big movie geek” and was fascinated by the various responsibilities of the crew. The experience has inspired her to go back to school for directing and production design. Yoon was also struck by the attention to detail that goes into each element of a movie’s mise-en-scène, including the costumes and set decoration. “There are so many things you don’t notice at first that add detail.”

As much as she enjoyed being on set, Yoon believes her true work is at a writing desk. “I’m a book person. All I want to do is be in my little room, writing books.”