Believe it or not, those imaginative second-grade heroes of Dav Pilkey’s famed Adventures of Captain Underpants series, George and Harold, turn 20 years old this year. Befitting their well-known status, they can also be seen on the big screen. The 3-D animated version, Captain Underpants: The First Epic Movie, starring the voices of Ed Helms, Kevin Hart, Nick Kroll, and Thomas Middleditch, just opened. (Seriously, who wouldn’t want to hypnotize their mean school principal into thinking he was a tighty-whitey caped superhero?)

The author, the books, and, yes, even the underpants will be celebrated at Scholastic’s booth (1639). Nothing says family fun more than the opportunity to take a selfie in front of a giant four-feet-wide-by-two-feet-tall pair of underpants or hugging a giant Captain Underpants inflatable.

The Captain Underpants book series has more than 80 million copies in print and has been translated into more than 25 languages. Pilkey is also the author of the popular Dog Man series, of which Publishers Weekly said, “Readers (of any age) will be giggling from start to finish.” The first two Dog Man books debuted at #1 on the New York Times bestseller list. The next Dog Man book, A Tale of Two Kitties, will be published on August 29. Pilkey earned a Caldecott Honor for his picture book The Paperboy and a California Young Reader Medal for Dog Breath.

Not bad for a guy who started out with ADHD, dyslexia, and behavioral problems when he was a kid. Pilkey was so disruptive in class that his teachers made him sit out in the hall every day. He loved to draw and make up stories, so he spent his time in the hallway creating his own comic books. That’s when he created Captain Underpants and Dog Man. We spoke with the former teacher’s nightmare who USA Today called “the savior of the reluctant reader.”

We can’t believe Captain Underpants has been around 20 years. When you first started writing the series, did you think it would become such a touchstone in several generations’ childhoods?

I had no idea. My goal was, I wanted it to be perhaps a trilogy. I had no idea I would be working on it 20 years and 12 books later. I was very surprised at how it took off.

How were you able to tap into little kids’ psyches so intimately?

I am very immature. There is a part of me that is still a second grader at heart, so it’s not much of a stretch for me to write from a second grader’s point of view. I was not a lot of fun for the teachers, but a lot of fun for the class. In the hallway, with nothing to do, I started drawing and making comic books. It was a way for me to remain significant to my class because I would share my stories with my friends. I was diagnosed with extreme hyperactivity; they didn’t have the term ADHD back then. My parents were keenly aware that I was struggling, but they were so encouraging when I came home. They encouraged me to make my comic books. It meant everything to come home to such a safe atmosphere.

You are the reason many struggling readers finally learned to read. Why do you think kids love your books so much?

They identify with the characters, George and Harold, and their friendship. George and Harold are the heroes, but they don’t have superpowers. They have their imagination and ingenuity to save the world. Everyone can use their imagination and creativity.

Jerome Horwitz Elementary School is an homage to Curly, one of the three stooges, whose real name is Jerome Horwitz. Were you a big Stooges fan?

My local UHF station used to play The Three Stooges every afternoon. I‘d run home to watch that. The slapstick humor really carried over into my work. They were so joyfully ridiculous. That is Captain Underpants’ personality as well. I got a lot from Larry, Curly, and Moe, and even Shemp.

Now Dreamworks is releasing the movie. Were you involved?

I was really involved in the beginning. I wanted to go with Dreamworks because they preferred 3-D animation. They didn’t want it to be live action. No one wants to see someone running around in his underwear. I was involved because I wanted to make sure they stayed true to the books and the themes. When I was sure it was in good hands, I stepped away and let the creative people do their jobs.

Today, 10:30 a.m.–noon. Dav Pilkey signs copies of the first book in each of the Adventures of Captain Underpants and Dog Man series in the Scholastic booth (1639).