Garth Nix is a New York Times best-selling author of young adult fantasy series, including “The Keys to the Kingdom” and “The Old Kingdom” series. His most recent novel, “Goldenhand,” is the next installment of “The Old Kingdom” series.

The Harvard Crimson: What made you revisit the “Old Kingdom” series—were there any unanswered questions or stories you felt were left unfinished in “Abhorsen” and the prequel, “Clariel?”

Garth Nix: It was not really about questions unanswered, at least on my part. I have stories that sort of stick in my head for quite some time, and in fact with the Old Kingdom, I’ve had a number of stories floating around for a long time. Typically when I’m writing one of them, I think of several—there are probably half a dozen books I could write coming out of each of them in the past, and I make notes and I think about those stories and eventually one of them will rise to prominence and I’ll decide I have to write it. But I guess I was always thinking about going on with what happened to Lirael and Nicholas Sayre. It’s a big world, I guess, and there are so many story opportunities to go back to and write a story either connecting to existing books or gaps I left between books. There are so many stories to tell that it’s very easy to return.

THC: In “The Old Kingdom,” a large aspect of the titular characters is how they deal with fear in the darker fantasy world you’ve created. Did you conceptualize the characters as fearful, or is their fear a realistic consequence of the world you built?

GN: It’s certainly something I work very hard at. I think for fantasy to work it needs to feel real; it needs to have a very solid foundation in reality. Of course, one of the best ways to do this is to make the characters feel real. In terms of them being in a fantasy world, I do tend to write my stories following the main character. I often don’t know much about my fantasy world until I start writing and not very much about the character either. I typically start with how I imagine a person in a situation, sort of like a frame picked out of a film, where I don’t know anything that’s gone before or coming after, and then I explore fleshing out the story and then the world and inevitably what happens to that character. But of course, [for] the Old Kingdom books, I’ve written them over many years and now there are five of them and several stories so I do know a lot more about the world. Normally, I start with a character in a very basic setting and explore with the character.

THC: What were the first film stills for the stories?

GN: There’s always a number of images in my head. For “Sabriel,” in 1995, I think they were a few key things. One was a picture of the wall with snow on one side and the green lawn on the other side so it looked like summer on one side and winter on the other. And that actually was a real photograph of Hadrian’s wall, and that gave me the idea for the wall that divides the Old Kingdom and Ancelstierre and how the seasons are split and it’s actually a separate world when you cross the wall. So I think that gave me some of the ideas. The actual opening scene of “Sabriel,” when she’s standing outside the school gates and the rabbit has just been run over and she’s in uniform—I had this fantasy world setting, and I had this young woman who was in her last year of school, and something’s just happened, and I didn’t know how it all fit together, but I found out as I wrote the book. For “Lirael,” I’m not entirely sure except probably the glacier of the clayr where she lives. A society of women who see the future. Probably one of the key images there was of her standing out as still wearing the uniform of a child even though she’s not when everyone else has graduated to wear the uniform of the clayr. She’s the only one stuck in a child’s uniform even though everyone else is younger than her. The image of her really standing out in this society.

THC: What books were inspirational to your world building or helped define your breed of fantasy and science fiction?

GN: You could probably mention any significant science fiction or fantasy author in the ’60s and ’70s. Other writers in other genres, especially historical fiction. People like Rosemary Sutcliff, Mary Stuart. Some more obvious things like Robert Graves’s memoir of World War I. That was quite important as there is a sort of World War I trench warfare element to the Old Kingdom. Nonfiction, some of that as well. I’ve always read a lot of history and mythology.

THC: The political themes in “Abhorsen,” such as the refugees in Ancelstierre, feel particularly potent and relevant in recent political climates. Were more topical plot points like that a way of using fantasy to explore reality?

GN: Part of trying to make the books feel real is to have things within your fantastical country that are very relevant to what is happening in our world or what happened in our world because, of course, the plight of refugees is something that’s been occurring for a very long time. I think in the real[ity] of the novels, the particular substitute of the Southerling refugees being forced across the wall, really to get rid of them, is actually a reflection of what was happening—and is still happening—in Australia, where the government was turning back refugees on boats and was really doing everything possible to not let them come to Australia and get rid of them and get them to various other islands. So that was a reflection of that shameful activity. I’m not sure I was consciously trying to make a political statement, but in the way I wanted my fantasy world to feel real, I made connections to the real world and an aspect that got in the book and was a reflection of what was going on.

THC: Which places in your novels would you most like to visit?

GN: Many of the places I would like to be real—I love the Abhorsens’ house at the brink of the waterfall, although I would probably be scared of the stepping stones. I’d want to have the bridge that was there in Clariel’s time. I love the Library of the Clayr, although I’d be scared to go into it without a large band of armed librarians to go with me. Many of the places involve a large amount of wish fulfillment, so I put them into the books.