Today marks the release of the 13th and final book in the Treehouse series written by Australian author Andy Griffiths, and illustrated by Terry Denton. The series launched in the U.S. in 2013 with The 13-Story Treehouse, introducing boys Andy and Terry, who are trying to write a book but get caught up in the many distractions in their multi-tiered treehouse. The series has gone on to sell more than 13.5 million copies combined in the U.S., U.K., and Australia. Friend and fellow author Jeff Kinney, creator of the Diary of a Wimpy Kid series, spoke with Griffiths about bidding farewell to the Treehouse.

Jeff Kinney: I want to say sincerely what a wonderful privilege this is for me. I really admire and respect you, and I am proud to call you a friend. I think one of my favorite things about you is that you take comedy seriously. Why do you do that? What is it about comedy that you love so much?

Andy Griffiths: I feel exactly the same way about you, Jeff. Your books and work ethic and humor have always been a great inspiration to me. Right at the beginning of the Treehouse, how I conceived that was after reading a Wimpy Kid book’. I could tell you took comedy seriously, too. Because, number one, we all love to laugh. That’s the first thing you notice when you work with kids is they’re ready to laugh. And what a great piece of catnip to put in a book if you’re trying to encourage the habit and the passion for reading. ’I love to laugh myself, and I love to get kids reading—so I went, “How can we supercharge that comedy and make it really effective so that everyone is super happy?”

Kinney: It seems like you’re always breaking the rules. So why is it so much fun to break the rules in life and in writing?

Griffiths: Well, I think that’s what children’s books are for: to read about characters who do not do the right thing. They break the rules, either legal or social or moral. And we, as readers, enjoy secondhand that feeling of watching them get into trouble, watching them get their comeuppance in various satisfying ways. The fictional character does all the things that we would not do in real life. And that’s the great joy of a book: you’re living through that character without having to suffer the consequences yourself.

Kinney: That’s really interesting. I’ve never thought of that before. It’s like a vicarious kind of experience.

Griffiths: Yeah, and early on, I encountered resistance where adults would say, “I don’t think you should be showing the character doing that bad thing because then kids will think it’s okay to do it.” And I’d say, “No, no, this is the whole point. They can thought-experiment.” And what I found by trial and error was that if you have a character who does the wrong thing, but does not suffer an appropriate consequence—like they can be mean to a friend, for instance—but if they get away with it, it’s not a very satisfying reading experience. Because there’s some part of you that’s going, ‘Oh, he did that bad thing and he didn’t suffer. That’s not a good story.’ But what I would do is make my characters do the wrong thing, break the rules, and suffer double than anyone else would suffer. Ultimately, they get their comeuppance and then you feel, “Ah, a story has been told. Justice has been dealt.” So I would often argue to the adults. I’d say, “Yeah, they do the wrong thing. And look what happens.” The one who loses out, that is a moral lesson, but it also follows storytelling rules.

Kinney: Let’s talk about the last chapter of the Treehouse series: 169 levels. Did you ever imagine the Treehouse would get so big?

Griffiths: No, Terry and I had the great luxury throughout the 2000s of just being able to experiment with all types of formats and all types of comedy. Because we’d done this enormously popular series in Australia, the Just series—Just Tricking!, Just Annoying!, Just Crazy!—we kind of had a license to do whatever we wanted. And one of the things in those books was, Terry would just illustrate around the edges of the pages, little flick pictures, little MAD magazine-style commentary. And as the series went on, I realized he was creating an entire book in the margins, and it might be in my interests to shut up a bit, reduce my words, and bring his pictures into the spotlight. And occasionally we’d get together and have a great time laughing and inventing and playing, as if we were 10-year-olds just getting away with something. He’d say, “Look at this silly drawing.” And I’d go, “That’s brilliant! I’m gonna write something to match it.”

And so this collaboration just organically started, which through a number of experimental books, led us to the first Treehouse. It was like sketch comedy in book form. But then I thought, “Well, people really like a long-form narrative,” which I’d learned from The Day My Butt Went Psycho. And I said, “What if you booked a long-form narrative, beginning-middle-end? And did the sort of sketch comedy along the way? You would have the best of both worlds.” So The 13-Story Treehouse was an attempt to get the pictures to do as much of the storytelling as the writing. This suddenly opened our audience up in Australia to a much wider [readership], because we toned down the humor a bit too. We weren’t quite as gratuitously violent or disgusting as we had been. And we discovered not everyone needs 80% violence in a book—maybe 10% is enough. And suddenly, we had this book, which then went around the world, and we were amazed.

Kinney: As a bookstore owner, I’ve seen your popularity here grow and grow, and I think that the moment I realized how big you were in the States was when one of my neighbors wrote a letter to you. A fan letter, and you recognize the name of the town. Talk to me about the investment you’ve put into touring in the U.S., because it seemed pretty extraordinary.

Griffiths: Well, I had to invest in touring in Australia right from the beginning. Because obviously in the beginning, books don’t sell a lot. But I’ve been a high school teacher. I’ve been a frontman in a punk rock band. I was very much of the do-it-yourself kind of philosophy. If you make something then you’ve got to get out and let people know. So going around schools as a visiting author was a very natural kind of extension of what I’d been doing. And I discovered I loved it, and I studied stand-up comedy techniques, so I could make those really work. The more I [did] it, the more people would kind of hook into the type of humor that I do. And it was very much educating the audience as to what the humor was. I found the more I was out there explaining, showing, convincing the skeptics—because they would see the kids rolling around on the floor laughing and they go, “Oh, he’s not a subversive anarchist. The kids really like this,” and then they rush off and read all the books. [It] took them a while.

Kinney: When did you realize that it would translate here in the United States? What were the first signs that you might find a bigger audience here, as well?

Griffiths: Well, it was a rocky road with the States. Initially The Day My Butt Went Psycho was published back in the early 2000s by Jean Feiwel. And that did extraordinarily well. Head-scratchingly well. And I came over for a tour—half of the dates of which were canceled when the schools found out the book title. But it was a wonderful introduction to the States, [and] to the size of your kids’ book market. Because, coming from a small country like Australia, to see the vastness of it was something else.

But we also have a tradition when a rock and roll band gets big in Australia. The question is, “Yeah, but can you make it in the States? Will it translate?” Because we’re all sort of thinking, we’re doing how we do it here, but it’s not proper until the States or the rest of the world give us a pat on the head. So [there’s] a long tradition of bands going over to the U.S. [and] exploding during the relentless touring because they can’t stand each other or the pace of the touring. That’s a sad story for a lot of bands. But I’d say yeah, that ethic was just in me and it was really fulfilling to work with kids with a slightly different sense of humor. And as you would know, all the weirdness of touring, like [you’re] just going to turn on a light switch, work out which way the taps go—that’s really good for you as a writer. You’re filling up your tank with H20.

Kinney: That’s a good way to put it. So I’ve had the pleasure of seeing you interact with kids many times. And I think it’s really fun seeing teachers try to contain kids while you’re simultaneously winding them up. Do you have a guiding principle when speaking with kids?

Griffiths: My first principle is simply to make an impact on them. And I assume I’m one of a long line of speakers who the kids are not that enthusiastic about, who’s going to bark at them for the next 45 minutes. So I try to subvert that right from the beginning. I’d say, “Oh, I’m so sorry I’m interrupting your school today and you’d rather be doing math with your favorite teacher.” [They’d say,] “Oh, no, no, no, no, we’d rather be here!” And so they get the sense that I’m going to be fun. And that I’m going to talk to them and not at them. And then you can sort of play, but I know where the limits are. And I like to go really close to it. And I very rarely lose control.

I would describe it as a playful relationship that you can have with the parent or child, messing around. And you can’t always tell what’s going to happen. But you’re being comfortable with uncertainty in a presentation, [and that] makes it electrically interesting. But what I do notice from the U.S. style of presentation in general—because I’ve had other U.S. writers [say] “I cannot believe you gave them water pistols and invited them to have a fight.” it’s a much more structured presentation in general that most writers will do. And as a comedian, my instinct is to subvert. And that appears unstructured to a certain extent.

The first thing you notice when you work with kids is they're ready to laugh. And what a great piece of catnip to put in a book.
– Andy Griffiths

Kinney: I like that. Like I said, I’m still learning a lot through this interview.

Griffiths: You’re one of my best students, Jeff. Because I know when we first met in Australia—and that was a huge thrill and highlight for me—and you were worried that your presentation was a bit conventional [compared] to my free-wheeling, and we talked a lot about it. And these days, you have a rock-star presentation, [with] all sorts of uncertainties all built into it.

Kinney: My next book is called Hot Mess. So I just got off a call planning the Hot Mess tour. We’re going to Oregon to have giant meatball fights and things like that. So yes, I may have stolen from your spirit there and captured it.

Griffiths: I’m very proud. The student has become the master.

Kinney: So my last question for you is: Andy and Terry, the characters in the book and of course reflective of you in real life, are always on deadline for their next book. So can you tell us anything about your next deadline?

Griffiths: With the 13th book, we’ve entered the end. It felt like we certainly exhausted Terry because there’s 1,000 things in every book. I think he’s going off into a well-earned, dignified retirement now, and I thought I was, but our publisher in Australia had other ideas and introduced me to a young, very talented illustrator called Bill Hope. And I couldn’t see how I’d ever have a replacement for Terry, because he is unique in so many ways. But I sent him some writing and Bill started sending me back some drawings, and I was like, “Oh, wow, he knows what I’m on about.” I can see he’s taking the ball and running with it, which then allows me to run even further. And so to my surprise, we’ve created the first book of a new series.

The series will be called Adventures Unlimited. And the first book is called The Land of Lost Things. And a little innovation in this book—perhaps it’s a big one—is the question I’ve been asked the most by kids: “Can you put me in the book?” For 13 years. “Can you put my friends in the book? And here’s a picture of my dog—can you put my dog [in the book]?” And I’d really like to do that, but I can’t because it’s me, Terry, and Jill, and there’s only so many characters. In this [new] book, the main character is me, but the other character is you—the reader. So now, rather than me use Terry as my whipping boy, you are the Terry character. We’re famous adventurers. We go on an adventure each book, and it’s me and you. So the first line is, “We’ve had some amazing adventures together, haven’t we? Remember when we did this? Remember when we did that? What, you don’t remember? Well, let me remind you.” That’s how I’ve always written: I write to the reader and acknowledge that they’re there. It’s like a choose-your-own-adventure, except that I don’t trust the reader to make the right choices. Now I’m going to drive this thing, and then we’re going to have a great adventure in each book.

Kinney: That’s hilarious. Well, congratulations on wrapping up the 13 books in the original 13-Story Treehouse. It’s an amazing accomplishment. You’ve contributed a lot to humor and to kids’ reading and we really can’t wait until we see what you come up with next Thank you.

Griffiths: Thank you and I can’t wait to see what a big Hot Mess you create.

The 169-Story Treehouse: Doppelganger Doom! by Andy Griffiths, illus. by Terry Denton. Feiwel and Friends, $16.99 Apr. 2 978-1-250-85021-8