It's not easy to pin Kenneth Oppel down. In over a dozen novels, the bestselling YA author has swung his lens from bats to blimps, from trains to time travel. His latest, Every Hidden Thing, is a rip-roaring historical adventure set in the golden age of dinosaur discovery... with a little star-crossed romance thrown in for good measure.

In his own words, Oppel reveals how this page-turning palaeontology tale came to be — from tagging along on dig sites to letting a strong-willed character tell her own story.

"Every Hidden Thing really started with the idea of discovery. I was thinking about how exciting it would have been to have been the person digging a big hole in the ground and discovering an enormous bone that could not have belonged to any animal on Earth at that time. So I started researching the historical context of who these people actually were. I'm sure it's happened throughout undocumented history, but the real boom time for discovering dinosaurs was the 19th century.

"I came across this early research by two duelling palaeontologists at the time, Othniel Charles Marsh and Edward Drinkwater Cope. Such hugely amusing names! They were struggling to claim the first stakes in the science of palaeontology before palaeontology was even a thing — before the science even had a name. These two guys were competitors and absolutely hated each other. They tried for decades to destroy each other's careers, they argued in journals, they brawled at dig sites. I thought, 'Wow, these guys alone would make great characters,' but they were adults.

"So for me, the next irresistible step was to ask, 'What if each of these guys had a kid, a son and a daughter, and the kids connected in some way?' The parents would be mortified if the kids fell in love with each other. And Sam and Rachel came from there."

"I knew basically nothing about dinosaurs going into this book. So I started by reading a lot, but I also thought I should go out into the field, seeing as that's really where Every Hidden Thing is set. I reached out to the curator of dinosaurs at the Royal Tyrrell Museum in Drumheller, Alberta, and he responded that I was welcome to join him and his team on any one of three field trips they had planned. I chose the most comfortable trip, of course — which was based at their permanent field station in the park, with cabins and running water.

"And that's how I came to spend five days as the guest of three very patient palaeontologists in Dinosaur Provincial Park, Alberta, in some of the restricted parts of the park. They were prospecting, they were quarrying, and I also got to spend an afternoon back at the lab where they preserve the fossils. It was a crash course, and the actual work has changed very little since the time when the book is set. You walk and you look. You look for certain patterns. The rock erodes every year, a little more, so that park is an endless source of finds.

"I was just in awe of how good these palaeontologists were at knowing instantly the difference between rock and petrified bone, especially as there are bones everywhere, just lying on the ground. I did help dig out a hadrosaur and they put me really far out so I didn't damage anything, but the thrill is that first glimpse of bone. Meanwhile, I was taking notes like mad. I took photos, I took videos, and at night I'd go back to the cabin and write up everything that happened."

"The characters of Sam and Rachel came to me fully formed right from the beginning, and part of that was looking at their fathers. When you look at these two men, you have all sorts of assumptions about who their kids would be. I like the idea of how mismatched they are. One of the problems I always had with Romeo and Juliet is that they fall in love in seconds, but as an author, that limits your options about where that relationship can go. I like stories where external things may try to break them apart, but it's internal too — I didn't want it to be an easy courtship. I wanted there to be a lot of reservations on Rachel's side, and as a young woman wanting to get into science at the time, she has lot at stake. She's somebody who's grown up concentrating much more on her interests and intellectual pursuits. And she's much more careful about getting into a relationship.

"The book alternates between Sam and Rachel's narration, and this is something that evolved. Initially Sam was the sole narrator. But increasingly I started hearing Rachel's voice too. The scene that really nailed it for me is when she's been left behind by her father, who's going off on an expedition, and she has to stay with her aunt. The first night there, Rachel lets snakes loose in her aunt's bed. I thought, that I love. It shows how determined she must be to do something so extreme and get herself on this trip. I also thought, that's who you'd really have to be as a young woman to get yourself taken seriously in this time. You'd have to be a fighter. And once I knew she was a fighter, I felt she had a voice and she had to be an equal character in the story. Rachel came through so clearly when I realized this."