When people talk about "cities on the move," they usually are speaking of improving economic conditions or a burgeoning social scene. When Philip Reeve talks about moving cities, he means it literally. A Darkling Plain (HarperCollins/Eos) brings his massive Hungry City Chronicles sequence to a close. With awards piling up and movies in the works, Reeve spoke with Bookshelf about the origins of his complex, ambitious epic.

What got you thinking about the whole idea of moving cities?

Moving cities are a fairly hoary old sci-fi trope—I seem to recall they were always cropping up on Doctor Who when I was young, though I may be misremembering. But I got thinking about them while noticing how my home town of Brighton was expanding and swallowing up the smaller towns and villages around it. I thought that would be quite an interesting reason for a city to move—so that it could catch and eat other cities.

The series' setting feels very fleshed out—almost as if you were researching a place that was already there. What year did you first begin imagining it?

I think I first put pen to paper in about 1994, although the book incorporates elements from previous things I'd done, going back to my school days.

Were there any books or movies that sparked some of your vision of that world?

Terry Gilliam's Brazil was a big influence—a fabulous retro-future envisioned by a man who really understands the appeal of ducts. There are obvious traces of Star Wars and James Bond and other movies from my childhood, as well as lots of less obvious influences, like the historical novels of Patrick O'Brian and Geraldine McCaughrean.

There's a hint of steampunk in there as well.

I think I was steampunk long before the term was coined. My first encounter with science fiction was reading the work of H.G. Wells when I was nine or ten, and I don't believe The War of the Worlds or The Time Machine have ever been bettered. Plus I have always had a liking for Victorian and Edwardian clothes and contraptions, which tends to color the worlds I dream up.

Are we wrong to look for metaphor in the books' concept of "municipal Darwinism?" Are you saying something about the ways neighborhoods "move" relative to one another (i.e. poverty, social conditions) in our world?

By all means look for a metaphor if you like! People seem to see it as a metaphor for quite a number of things, and that's great.

In A Darkling Plain, you bring the whole thing full-circle. Did you have that in mind at the outset?

I had no idea I'd end up writing four books when I completed Mortal Engines. I didn't even think it would find a publisher. So no, I just made it up as I went along, although I think I started to get an inkling of the ending while I was working on the third book.

Is the setting of the Hungry City books still alive in your head, or have you moved on to something else?

I think I've finished with that world, at least for the time being. I certainly wouldn't go back to those characters—I think they've all earned a nice long rest. I've just written a very gritty, non-magical take on the King Arthur legend, Here Lies Arthur, and I'm currently toying with some other historical ideas, as well as working with the illustrator David Wyatt on some sequels to my Victorian space opera Larklight.