Jeremy Siegel: This is GBH's Morning Edition. Later this year, something wicked is coming to the big screen. Ariana Grande and Cynthia Erivo are starring in the "Wicked" movie, an adaptation of one of the most successful Broadway productions in history, which itself is an adaptation of a bestselling book based on the children's novel "The Wizard of Oz." It was the author Gregory Maguire who 30 years ago dreamt up the idea of a retelling of L. Frank Baum's classic Oz through the eyes of the Wicked Witch of the West, who he named Elphaba.

Gregory Maguire: I invented the name by playing with the initials of the author, Lyman Frank Baum.

Siegel: That's Maguire speaking recently at the Boston Public Library.

Maguire: I try and Lafaba, I tried Lafeyba. And then I tried Elphaba. As soon as I got Elphaba, I thought, oh, that's it.

Siegel: The Wicked Witch doesn't have a name in the original tellings of The Wizard of Oz, both the Baum books and the classic film. That's something Maguire told me in our conversation at the library he wanted to change, even though when he first saw "The Wizard of Oz" as a little kid, the witch for him was a nameless terror. Were you scared of the Wicked Witch of the West when you were a child?

Maguire: I was terrified of her. I'll get you, and your little dog! And I was also scared, of course, of the flying monkeys. But by the time I'd seen the show maybe five times — so maybe I'm 10 years old now — I began to realize that the wizard —who lied to Dorothy, who sent her off into danger with no expectation of being able to pay his debt to her, was just as scary, if not, in fact, scarier. The witch? Yeah, you know, she's menacing to my dreams still. But she never lied. She never lied to Dorothy. She never tried to trick her. She said exactly what she felt. And she did exactly what she said she was going to do. The wizard dissembled and lied and put Dorothy and her friends at grave risk. And so, in a way, as I say, I think the story of Wicked began by watching the film and by ingesting and digesting what it was saying about power structures.

Maguire: When I was little, after we watched the movie, you know, I was kind of the boss kid. I was the middle kid, for one thing. But I was also the idea man, you know? So when little kids had to be babysat, I was young enough to be forced to do it. And I was old enough to have ideas for what to do next. So after "The Wizard of Oz" showed, I would gather my brothers and sisters and the kids around the neighborhood and I'd say, we're going to put on "The Wizard of Oz" this afternoon, guys. It's going to be in the backyard. And I would assign parts and we'd all sort of play it out.

Siegel: You were already creating I was a "Wizard of Oz" as a child.

Maguire: I was already creating. So the funny thing is, it's a 92 minute film — it actually, if you take out all the music, you can run through the whole story in about 12 minutes. So we would run through the story and then, you know, I would have to babysit for another, you know, 90 minutes. What are we going to do next? So I'd started losing my crew. And I'd say people, people listen up. We're going to do this again. We're going to try it again. We're going to mix it up a little bit this time. I would do some cross-gender casting a lot earlier than it was considered respectable to do. I would say, okay, Michael, you can be the Wicked Witch of the West. And Matt, you can be Dorothy and Annie, you can be Captain Hook. And Annie, who was five, bloody little fundamentalist, would say, 'but that's not right. There's no Captain Hook in this story.' And I'd say, 'Excuse me, I'm the author.' But, you know, you add just one new element to what you already knew, and the story cannot end the way that it used to. The story has to be different. And so, in a way, my ability to write stories was a result of my ability to play like any child's ability to play, to take what you have and make something new out of it. If that doesn't work, take it again, scramble it up and make something new again. So once you do that, you own the story. Now it helps if the story is in the public domain. When I wrote "Wicked," I did not know — this was one of the many pieces of good luck in my life. I did not know that as I was writing the novel, the estate of L. Frank Baum was months away from coming out of copyright. I had assumed it was in the public domain already for decades, and I never thought about it. I sent my manuscript to my agent in 1994, and he said, how did you get to be so smart? This has only been out of copyright for six weeks.

Siegel: And you accidentally did the savviest job.

Maguire: It's Good luck. I was the first one out of the gate by my good luck. And Instinct, I suppose.

Siegel: And so, Maguire tells me, "Wicked" was born out of good luck and a knack for messing with things that already exist, and making a point while doing it. Three decades later, "Wicked" is now synonymous with musical theater after the adaptation's smashing success on Broadway. Come November of this year, it's all but certain to be a blockbuster. But despite being the wizard of Words behind it all, Maguire says at this point his world of Oz has become a world of its own, one where he's kind of on the outside.

Maguire: I have not seen the movie, nor did I even know that the trailer was being dropped at the Super Bowl. Nobody tells me anything. Nobody sends a postcard to the old grandfather that says, grandad, wake up from your nap. You know, turn on the Super Bowl for the first time in your life and watch something interesting.

Siegel: So you weren't watching?

Maguire: I wasn't watching. Everybody else in the world saw it before I did. But the next morning my media, as they say, blew up and I went and found it. So I have not seen a cut. But Jeremy, what I did do was about, well, almost a year ago, I went to London and I hung out at the soundstages in Elstree Studios in Borehamwood, north London, to watch about five days of filming. I do have to be mum on some things, but what I can speak about with alacrity and passion is how much I learned about the art of acting by watching Cynthia Erivo, Ariana Grande and Jonathan Bailey. I was amazed at the capacity of people that I think of primarily as singers to be as talented and as precise and as intellectual in their approach to the reading of a scene as they are to the shaping of a melodic line, let's say. It was mind-boggling for me, whose mind likes not to be boggled.

Siegel: That was author Gregory Maguire, who tells me, despite being the mind behind the reinvention of Oz, he plans on waiting to see the Wicked movie in the theater later this year like the rest of us. We spoke from the GBH studio at the Boston Public Library's Newsfeed Cafe. You can find a video of our full conversation on the GBH news YouTube page. That's youtube.com slash GBH news. You're listening to GBH's Morning Edition.

“Wicked” author Gregory Maguire, who now lives in the Boston area, has been re-imagining the story of “The Wizard of Oz” since he was a child.

“I was the middle kid, for one thing. But I was also the idea man,” he told GBH’s Morning Edition co-host Jeremy Siegel. “So when little kids had to be babysat, I was young enough to be forced to do it. And I was old enough to have ideas for what to do next.”

He would wrangle his siblings into his own productions of “The Wizard of Oz,” L. Frank Baum’s fish-out-of-water tale of adventure and friendship. And after a while, he started to remix the story.

He tried gender-bending his casting and inserting characters from other stories, like Peter Pan’s Captain Hook.

“You add just one new element to what you already knew, and the story cannot end the way that it used to,” he said.

His 1995 book “Wicked” — a retelling of L. Frank Baum's classic Oz through the eyes of the Wicked Witch of the West, who he named Elphaba — has been turned into a wildly successful Broadway musical and, later this year, a film adaptation starring Ariana Grande as Glinda and Cynthia Erivo as Elphaba.

“In a way, my ability to write stories was a result of my ability to play like any child's ability to play, to take what you have and make something new out of it,” he said. “If that doesn't work, take it again, scramble it up and make something new again.”

The Wicked Witch of the West doesn't have a name in the original tellings of “The Wizard of Oz,” either the Baum books and their film adaptations. That's something Maguire said he wanted to change.

“I invented the name by playing with the initials of the author, Lyman Frank Baum,” he said. “I tried Lafaba, I tried Lafeyba. And then I tried Elphaba. As soon as I got Elphaba, I thought, oh, that's it.”

When he first saw "The Wizard of Oz" as a little kid, the witch for him was a nameless terror.

“I was terrified of her. And I was also scared, of course, of the flying monkeys,” he said. “But by the time I'd seen the show maybe five times ... I began to realize that the wizard, who lied to Dorothy — who sent her off into danger with no expectation of being able to pay his debt to her — was just as scary, if not, in fact, scarier.”

Exploring the story from Elphaba’s perspective began with Maguire “ingesting and digesting” what the story was saying about structures of power, he said.

“The witch? Yeah, you know, she's menacing to my dreams still,” Maguire said. “But she never lied to Dorothy. She never tried to trick her. She said exactly what she felt. And she did exactly what she said she was going to do.”

Three decades later, "Wicked" is now synonymous with musical theater after the adaptation's smashing success on Broadway. Come November of this year, it's all but certain to be a blockbuster film, too.

But despite being the wizard of words behind it all, Maguire said at this point his world of Oz has largely become a world of its own.

He got to go to Elstree Studios in Borehamwood, north of London, to watch about five days of filming for the upcoming movie.

“What I can speak about with alacrity and passion is how much I learned about the art of acting by watching Cynthia Erivo, Ariana Grande and Jonathan Bailey,” he said. “I was amazed at the capacity of people that I think of primarily as singers to be as talented and as precise and as intellectual in their approach to the reading of a scene as they are to the shaping of a melodic line, let's say. It was mind-boggling for me, whose mind likes not to be boggled.”

When a trailer for the film adaptation aired during this year’s Super Bowl, Maguire said, he wasn’t even watching. He had no idea it was coming.

“Everybody else in the world saw it before I did,” he said. “But the next morning my media, as they say, 'blew up' and I went and found it.”