Over the course of his career, law dean Simon Chesterman has written 16 books on heavy, scholarly topics such as governance and international law.

For his 17th book, he has switched gears. He is taking on the world of young adult fiction with his first novel, Raising Arcadia.

The story centres on 16-year-old girl genius Arcadia Greentree, who studies in a school which counts among its alumni members of British royalty.

With her logical mind, she is used to unravelling mysteries. But she soon discovers that her identity might itself be a mystery: Arcadia Greentree should not exist. She is, instead, part of an experiment that hopes to establish whether a person is defined by his genes or his upbringing.

Peppered with codes, puzzles and shocking twists, Raising Arcadia is the first book in a planned trilogy. Chesterman is already working on the second instalment.

The 43-year-old Australia-born dean of the National University of Singapore Faculty of Law first came up with the idea for the book because he wanted to write something his children - a son aged 11 and daughter aged eight - would read.

One of his toughest critics yet, he says with a laugh, is his daughter.

"She doesn't mince her words. She's quite commanding actually," says Chesterman,whose wife Ming Tan is the director of Como Foundation, the philanthropy arm of Como Hotels and Resorts.

"She's on my back telling me not to have quite so many murders. She would like different crimes and - most importantly - she wants me to guarantee a happy ending at the end of the series."

The book explores a topic that has long fascinated Chesterman: the tension between nature and nurture.

As a law professor, he has seen young men and women go to university, eager to learn.

"But how much of an influence do we really have on them and how much is genetic make-up?" he says. "So that question of what shapes someone is something I could explore in this book, not in an academic sense because that's not my area of research, but in a fictional sense."

Chesterman grew up reading the works of mathematician Martin Gardner, the man behind dozens of books on puzzles, and Alice's Adventures In Wonderland author Lewis Carroll, who also wrote on symbolic logic.

So it is no surprise that he weaves puzzles into the story.

Arcadia's mother, for example, leaves a puzzle out for her each week - something Chesterman and his wife occasionally do for their children. Some Saturday mornings, they leave a puzzle out for their kids, who have to solve it in order to find the money to buy breakfast.

Chesterman spent six months mapping out the plot. After turning in a book on the law and practice of the United Nations in the middle of 2014, he started writing the novel in snatches of time: late at night and in the early hours of morning, on long-haul flights and train rides overseas.

"Arcadia was kind of my reward, something lighter and a bit more fun for me to write," he says.

"It was more relaxation than work, like, 'Okay, I've cleared all my e-mails. I'll treat myself to some writing.' It's probably the book I'm most excited about - except for my first."

He is now five-sixths of the way through the second book in the series, which is slated for publication this November. It will be launched at the Singapore Writers Festival.

Words have been a lifelong passion for Chesterman, who was born in Australia and did his doctorate at Oxford University in the United Kingdom.

He was an avid writer in his teens, churning out two "completely unpublishable" novels. "I'm delighted this was pre-Internet, so I didn't just sort of upload them, and then live a life of regret."

As an adult, his writing tended towards the academic: opinion pieces for newspapers and books bearing titles such as One Nation Under Surveillance: A New Social Contract To Defend Freedom Without Sacrificing Liberty.

He is used to writing for a professional and scholarly audience, but fiction was a new challenge.

"The hardest thing about it is the sense of being exposed and vulnerable," he says.

With academic work, readers might disagree with the arguments presented - but a professional distance remains. Fiction, however, is much more personal.

"There's so much more readers can judge - and they might end up completely hating it."

He and his family discussed whether he should publish the book under a pseudonym, but he decided not to because "there's no shame in an adult writing - or reading - young adult fiction".

Echoing the intentions of many young adult writers, he adds: "I think there's a real space in the young adult world for what I hope is thoughtful and thought-provoking literature.

"I wanted to write something that's aimed at young people, but takes them and their concerns seriously, and treats them like adults - while also having enough in there for actual 'adults' to enjoy."

• Raising Arcadia by Simon Chesterman (Marshall Cavendish Editions, 2016, $18.60) is available from major bookstores.

• There is a book discussion of Raising Arcadia with Simon Chesterman and Adrian Tan at Neo Kinokuniya Singapore Main Store, Ngee Ann City, on July 16 at 2pm. For more information, go to www.facebook.com/events/1755716634667906/