The prolific author appeared at the Hong Kong International Literary Festival last week to discuss his latest novel, The Terrible Thing That Happened to Barnaby Brocket. Boyne's third children's book, published in August, is due to be translated into 23 languages. It shares themes found in some of his 70 or so short stories and 11 novels - young people being rejected and left alone, and friendship between children.
"Barnaby is a boy whose body doesn't obey the law of gravity; he floats," says Boyne, 41, best known for his 2006 novel, The Boy in the Striped Pyjamas, which sold more than five million copies and was made into an award-winning feature film two years later. "His parents don't love him because of that; he is lonely."
Barnaby has to stay weighted down or he will float away. But when he is eight, his embarrassed parents decide they have had enough - and make him float off.
Focusing on such a theme was "a subconscious choice", Boyne says. "I think many children are being abandoned or 'exiled' in a certain way because they are different. Most children are afraid of whatever makes them different, but it is what makes them different that makes them special."
He had first-hand experience of loneliness, he says. "As a teenager, I was bookish and shy. I wasn't confident. I didn't have many friends. I felt lonely and just wanted to grow up and get out of it."
Yet he was confident about what he wanted to do with his life, he says. "When people asked me what I wanted to do when I grew up, I'd say I wanted to be a writer. I always knew I would be one."
To hone his skills, he took writing courses and joined critique groups. "As a young writer, you need other people to look at your work and tell you what they think. It's important for you to listen to criticism, even though you may not agree with them. You also learn a lot from critiquing other people's work."
He says he's been a compulsive reader - a "readaholic" - all his life. Even now, he seeks out new, first novels by others and helps to promote them if he likes what he reads.
"I'd tell people when I read a good novel," he says. "I'd introduce the author to them and buy them copies. When I first started publishing, nobody really helped me, so I want to support the new generation of novelists."
Being an internationally known author, whose books are published in many different countries, can be exhausting, though, he says.
"You need to go out and meet your readers, and I enjoy meeting them. But I'm away from home a lot, always living out of a suitcase in a hotel," he adds.
"Being an author doesn't mean you'll become someone else who likes to be on stage, or a salesman [promoting books], yet it's all part of the job ... Ideally, I want to be just writing in my office at home."
Nonetheless, he says it is impossible to imagine a time when he will stop being a writer.
"Writing defines who I am," he says. "Being someone who loves novels and having the ability to write them is wonderful."