Terry Denton, Illustrator of the Treehouse Books, Dies at 76

Terry Denton, the Australian illustrator whose drawings made the Treehouse series a fixture of children's publishing, died on Monday, September 21, 2026, surrounded by his family near Melbourne. He was 76. ABC News said his publisher and his literary agency announced the death. The Bookseller published Macmillan Children's Books' tribute the next day.

No cause was given. ABC News said he had been in poor health in recent years.

The commercial fact is the series. Gaby Morgan, associate publisher at Macmillan Children's Books, told The Bookseller that the house began publishing Denton's collaborations with Andy Griffiths in 2010. The Help! and Just! books were popular at once. "It was the Treehouse series — 13 books of 13 storeys each — that truly took off." Morgan said the series is now in 35 languages and has sold more than 13 million English-language copies worldwide. ABC News reported that The 13-Storey Treehouse was first published in 2011, and that The 78-Storey Treehouse became the fastest-selling book in Australian history when it went on sale in 2016.

Thirteen books, thirteen storeys, a deadline they never met

The joke of the books is a publishing deadline. Fictional versions of Andy and Terry live in a treehouse and try to finish a book while the treehouse keeps interrupting them. Griffiths told ABC they had always said they would stop at 13 books. "169 stories — 13 times 13 — seemed like the perfect place to stop." They did stop there. Griffiths said they had been surprised the books travelled. "The Treehouse was done just for kids in Australia and we had concluded it was too strong a flavour for any other country. To our surprise, it went worldwide, tickling the whole world's funny bone, including the UK, Norway, Holland, and South Korea."

Alison Ruane, managing director of Macmillan Children's Books, said: "For a generation of children — of every reading ability — a Treehouse book was often where a reading habit began. Parents loved them just as much as their kids did, and a new Treehouse book was one of the biggest, most eagerly awaited moments in children's publishing each year. Terry's artwork brought something all its own to that success: brilliantly detailed, clever, funny and often quietly informative, rewarding readers who came back to pore over every page again and again."

Morgan said the same curiosity ran through Terry Denton's Really Truly Amazing Guide to Everything (2020), which Denton wrote and illustrated, "a funny and fascinating whistle-stop tour of the history and science of the universe." With Macmillan he also published The Bumper Book of Silly Stuff to Do and The Bumper Book of Holiday Stuff to Do. The Bookseller said he published more than 30 books of his own. ABC News said he had already worked on almost 30 books when he met Griffiths in the 1990s, and that his Gasp! series was adapted for television. In 1986 he won the Children's Book Council of Australia Picture Book of the Year for Felix and Alexander.

A partnership, and then the family

Griffiths told ABC that working with Denton for three decades was "an honour and a pure delight." "I'll miss him forever, but he's at peace now. I'm incredibly grateful for his legacy, that we were able to get so much out to the children of Australia and the world." He called the partnership "a match made in heaven." "He had a complete lack of ego. In the books, we were mad at each other all the time, but in real life, it was a very harmonious relationship. We would supercharge each other. I would create a structure and he'd come in and throw a spanner in the works."

They lived on opposite sides of Port Phillip Bay, about an hour apart. Griffiths said he had not seen Denton for several years. "As his health declined, he spent all his time with his family, and I totally respected that."

Denton was born in Melbourne and grew up there, the second youngest of five boys. He is survived by his wife, Kristen, their children Imogen, Eve and Max, and grandchildren Georgia, Lucy, Charlie, Alfie and Felix.

For children's publishers the Treehouse books were a rare object: a series that was a joke about not finishing a book, that finished exactly when it said it would, and that still sold in the tens of millions. The drawings were not decoration on Griffiths's text. Macmillan's tribute treated them as the reason children went back to the same page. That is the illustrator's half of a bestseller, and it is the half Denton held.

Image: A bookshelf at Tuggeranong Library, April 13, 2025. Not a portrait of Terry Denton; no freely licensed photograph of him was available. Photo by Nick-D, via Wikimedia Commons, licensed CC BY-SA 4.0. Placed on a blurred extension of the same photo.

Sources

• ABC News: Terry Denton, children's author and illustrator behind Treehouse series, dies aged 76 (September 22, 2026)
• The Bookseller: Australian illustrator and author Terry Denton dies aged 76 (September 22, 2026)