There is very little creative down time for Jennifer L. Holm and Matthew Holm, siblings who have published novels separately (Jennifer is a three-time Newbery Honor recipient for Our Only May Amelia, Penny from Heaven, and Turtle in Paradise; and Matthew co-wrote Marvin and the Moths with Jonathan Follett) and have collaborated on a number of children’s books series. Their first joint project was the graphic-novel series Babymouse, starring a headstrong young mouse with messy whiskers and a wild imagination. Launched by Random House in 2005, the 20-book series has more than three million copies in print worldwide.

This summer and fall, the Holms have multiple pub dates to celebrate, beginning with the July 4 debut of Babymouse Tales from the Locker #1: Lights, Camera, Middle School! In this graphic novel,Babymouse, who is now in middle school, makes a calamity-filled attempt to write and direct a sweeping cinematic epic. Also due from Random on Independence Day is the siblings’ Comics Squad #3: Detention, and the publisher will release I’m Scared, the fourth installment of the My First Comics board-book series, in August. In September, Scholastic’s Graphix imprint will publish Swing It, Sunny, a sequel to the Holms’s 2015 middle-grade novel, Sunny Side Up. The prolific duo talked to PW about how they came to collaborate, how that process works, and about their new Babymouse endeavor.

Looking back, would you say the seeds for your creative collaboration were sown in your childhood?

Jennifer L. Holm: In a way, I guess they probably were. We are two of five children, and I’m the only girl, born right in the middle. Matt is the baby. From an early age, I loved to read, and Matt was always drawing and cartooning. When he was in fifth or sixth grade, he began drawing aliens from outer space—lots of them. At the time, it was a thing for kids to decorate their doors to reflect their personalities, and Matt would post his comics of space aliens on his door. Since my bedroom was right across from his, I’d be the first to see them.

Did your big sister give you favorable reviews, Matt?

Matthew Holm: Yes. Jenni seemed to like them, and hers was the only feedback I really got. Our parents were medical people—Mom was a nurse and Dad was a doctor. They both enjoyed reading, and Dad was a big comics fan, but they both were really unsure about anyone going into the arts and being able to make enough money to live. Still, they were always encouraging me, and let me take whatever art classes I wanted to in high school. But they’d ask, “What are you going to do when you get to college?” I ended up double majoring in English and art at Penn State, and was the political cartoonist for the newspaper there.

And did you continue on an arts path when it came time to launch a career?

MH: After I graduated from college, I moved to New York City and was working as an editor for Country Living magazine. Jenni was also living in the city, and when she was working on her first Boston Jane novel in 1999 or 2000, she asked me to do some proofreading and historical fact-checking, so I started helping out with that.

JLS: Yup, I sucked him in! And then a couple of years later, I started working on another book project, Middle School Is Worse Than Meatloaf, and I wanted to have the protagonist’s brother draw comics to communicate with her—so I asked Matt if he wanted to draw those comics for the book.

MH: I wasn’t sure about doing it, since it was the first time Jenni had art-directed me. But it went really smoothly—and that started her wheels turning about what else we might work on together.

And did that something else become Babymouse?

JLH: It did. I was a broadcast producer for TV commercials at Ogilvy and Mather at the time, and one day I’d had a bad time at work. It was one of those days that I now think of as a Babymouse day—when you forget your umbrella and it rains, and then you realize you’ve forgotten your lunch at home. I came home very grumpy, and an image popped into my head of an irritable mouse with crazy whiskers, standing with her hands on her hips. I called Matt and said I had a new book idea—and asked if he wanted to work on it.

Matt, did you immediately warm to the idea?

MH: Yes, it seemed like a good idea. Since college, I’d been trying to figure out a way to make some kind of a go with cartooning. I had done a webcomic, again about space aliens—I was very into them!—but really wanted to find a way to do cartoons for a living. When Jenni came to me with the Babymouse idea, I thought this might be a chance, and I thought it was an interesting angle, doing cartoons through a traditional children’s book publisher.

Did it take you long to place the series?

JLH: It was not an easy sell—it took us three years. At the time, most children’s publishers didn’t have art department pipelines in place to create graphic novels, or marketing pipelines in place, and no one really knew where to put the books on store or library shelves. So we felt as though we were saying, “Is it okay with you guys if we create a new genre?” and we were turned down a lot. Then I decided to go around to publishers to pitch the idea in person, and Random House got it right away. They had done well with Junie B. Jones and Magic Tree House, so they understood that audience. They bought the series in January 2004, and the first two Babymouse books came out in December 2005.

Would you say that the mechanics of your collaborative process fell into place easily?

JLH: Yes. Our style of collaborating on Babymouse partially grew out of Matt’s own writing background. We always collaborate on the general gist of a story, and then split up responsibilities. I do more of the writing, and Matt does all of the art. I create a story using a storyboard, and he revises my first draft. The beauty of collaborating is that you don’t have to have all the answers yourself. I’ll send a manuscript to Matt and leave big spaces blank, and tell him, “I need something funny here” or “I’m not sure this is really working,” and he’ll help fill in the gaping holes.

Matt, did you find your experience collaborating with Jonathan Follett on Marvin and the Moth a different kind of challenge than working with your sister on the Babymouse books?

MH: I did. Marvin and the Moth involved a totally different work style and collaborative relationship. We literally co-wrote the thing together. We’d get on the phone, open a Google doc, and talk through it as one of us typed. The book took us about 10 years to finish—partly because I was so busy doing the Babymouse books as well as books in Jenni and my Squish series—and he had two kids during that time.

JLH: Kids really do ruin everything!

MH: But they are so necessary to our business!

Speaking of children, Jennifer—have your two at all inspired Babymouse storylines?

JLH: My son is now 13 and my daughter is 10. Matt and I sold Babymouse to Random House when my son, Will, was three months old—so he has literally grown up with Babymouse! Historically, my children haven’t inspired any of the Babymouse stories, but Will did a little bit with Lights, Camera, Middle School! Part of the plot came from my previous life working in TV production, but another part came from Will and his best friend’s obsession with making movies on their iPads. They are both determined to be the next Steven Spielberg!

Have your own childhood memories come into play while creating the Babymouse books?

JLH: Absolutely. I pretty much am Babymouse. I really loved elementary school—those were the best years of my life, and it all kind of went downhill from there! I really love remembering all that happened in elementary school.

And what was the catalyst for sending Babymouse—and her friends—to middle school?

JLH: Well, since she first appeared in 2005, Babymouse has been in elementary school for 20 books—that’s a very long time for anyone to be in elementary school! Now, as she enters middle school, she’ll be growing up with some of her readers, and being a good friend to them during the hardest years of their lives. I remember reading Peanuts comics all through middle school as my comfort read.

MH: It is so much fun to see these characters move on. Some parts of their personalities are the same, and some aspects are amplified. In Lights, Camera, Middle School!, Babymouse becomes tyrannical as the movie director and bosses all her friends around. In elementary school, she got away with that kind of behavior. Her best friend Wilson—who was always very put upon—would just sigh at her and go back to whatever he was doing. But now, in middle school, her friends call her on her nonsense and don’t let her get away with it—they quit and walk off the movie set!

Did ushering Babymouse into the next chapter of her life present you with any new challenges?

MH: We switched up our procedure a bit. Lights, Camera, Middle School! is more like an illustrated chapter book than a traditional graphic novel. Jenni wrote the whole thing first, and then I pretty much did the illustrations on my own. Normally with graphic novels I do sketches, she does page layout, and I go back and redraw. This book was a bit of a different process. One thing that has helped us while working on books together is that earlier we had both worked in industries where our work was heavily edited and critiqued, and where we learned that it’s important to be pragmatic and let a person who knows how to do a specific job do that job.

JLH: Yes, you have to realize and have faith that the person responsible for a certain aspect of a project knows how to do it—and do it well. As a writer, I don’t believe in art directing too closely—I think you can cramp your artist if you over-direct. If you give artists freedom, perhaps they will take it in a different direction—and perhaps in a better one.

What’s in store next for Babymouse?

JLH: We’re working on Tales from the Locker #2: Miss Communication, which is due in July 2018, and a third book will come out the following July. The second story is all about having a cell phone in middle school and about social media. It’s something I’ve experienced with my own son, and it’s on everyone’s mind—kids and parents.

Given the Babymouse series’ sales tally, your heroine has obviously kept kids coming back for more. Is it gratifying to know that you’ve found the right mix of words and cartoons to engage readers, and that graphic novels are being widely credited for hooking more kids on reading?

JLH: It is quite amazing how the genre has taken off. Matt and I experienced the power of comics first-hand as kids. Our father had bound collections of classics like Prince Valiant and Flash Gordon, and we read them all, along with monthly comic books. With a graphic series like Babymouse, reluctant or casual readers can easily whip through the 96-page books, and that helps boost their confidence and build their reading chops. And that is gratifying.

Babymouse Tales from the Locker #1: Lights, Camera, Middle School! by Jennifer L. Holm and Matthew Holm. Random House, $13.99 Jul. ISBN 978-0-399-55438-4