Justin Cronin’s The Passage, the first in a projected trilogy, is a futuristic, post-apocalyptic epic about a world devastated by a vampire virus that turns humans into monsters. As the world falls apart, then attempts to rebuild itself, an orphan girl, Amy, becomes humanity’s last great hope of survival. Published by Ballantine in June, the foreign rights have already been sold to 26 publishers, and Ridley Scott’s Scott Free Productions have acquired the film rights. Cronin, author of two previous novels, The Summer Guest (2004) and Mary and O’Neil (2001), was born in New England and now lives with his wife and two children in Houston. With Kirkus Reviews, Cronin talks scary vampires, Arabian horses and why he loves his adopted city.

What was the inspiration for The Passage?

My daughter, who was about 8 at the time, now about to turn 14, basically dared me to write a book about a girl who saves the world. I think she was a little concerned that my books up until that point were not interesting enough. I said, “OK, why don’t you help me?” So we spent about an hour each day for three months in the fall of 2005 doing that. I would take my afternoon lunch and she would come along on her bicycle, and we spun out a story together. I had no intention of actually writing it. That was a bluff. I was just finding a way to spend time with my kid. But after three months we had what became the basic outline of The Passage. I decided to write down what we came up with. I thought it was pretty good. I wrote a chapter to see how it felt, and I never looked back.

Contemporary novelists who write about vampires—from Stephanie Meyers (The Twilight Series) to Guillermo del Toro and Chuck Hogan (The Strain Trilogy) to John Ajvide Lindqvist (Let the Right One In)—reimagine them in their own ways. How would you describe the vampires in The Passage?

In the book they are known by many different names [virals, smokes, dracs]. The proposition here is that these are the real ones, that all the vampires in lore and legend and popular culture, like most legends, are based on something real. I created a character, Lear, who goes looking for the virus that he believes is the source of the vampire legend. I wanted to write the vampire story without magic, to find the biological source of what is essentially a magical creature. I wanted to take the traditional characteristics of the vampire and give them a biological analogue.

The creatures in The Passage are human beings inflected with the virus. They are beings trapped in the moment before death. Their personalities have been erased. They are intensely bloodthirsty, violent predators that basically rip you in half and drain you of bodily fluids in two seconds. I borrowed a lot of things from the animal kingdom that were creepy or compelling, like the way fish move in schools in coordinated movements and groups. The vampires are not capable of speech, but they make a clicking sound from deep within their throats, a kind of speech modeled on the language of dolphins.

Themes of religion and spirituality are woven into the fabric of the novel. What role do they play?

It’s suggested in the book that documents and diaries produced by some of the characters are being studied at some distance in a future time by an academic conference. The names—“The Book of Auntie,” “The Book of Sara”—are suggestive of a new gospel. I wanted the book to contain a really broad canvas of time. For some future culture this is an aboriginal story, the basis of a new mythology, the story of Amy, the girl who saves the world…I wanted to write a story without magic, but one that does not rule out the participation of divine intelligence in the affairs of man.

The book has been both a critical and a commercial success, with over 650 Amazon customer reviews at last count. Any amusing encounters with zealous fans?

Everyone’s been great, though a reader who works for my British publisher seemed quite overcome. I was a little worried about him. I’ve never seen such an apostle for a book before. My reaction was, “Wow, it’s a book, dude.”

I’ve had readers before, but this is a book that has created a fan base. They feel personally invested in the characters. They don’t close the book and say it was good or bad. They kind of live with it. That’s the one thing I’ve noticed that’s striking and interesting. I don’t own these characters anymore. The public is a stakeholder.

Are you working on the second installment of the trilogy?

I’m writing it! It’s all mapped out. And the third book is already partially knocked out. I tend to work from pretty specific plans so that I don’t get lost in the forest. The publishing schedule is for every two years, so 2012 and 2014 for books two and three.

Does your daughter ever peek over your shoulder as you write the second book?

Yeah, but she’s a teenager now, and she’s completely consumed by that, as is the right of all teenagers. We still talk and she feels a connection to the story because she was there in its inception. She’s read The Passage thoroughly a few times. She’s a weirdly good reader in general. We were on vacation recently and she read 16 books. It was kind of creepy. By the end we were out of books, and I just gave her my Kindle.

You bought your daughter a pony as a thank you for her contribution to the creation of The Passage. How’s the horse?

He’s a small Arabian. His name is Teddy. He’s a good guy, a perfect gentleman. She’s outgrowing him pretty fast. Pretty soon she will need another horse. But yeah, Teddy’s a great guy.

You live in Houston. What do you like about living there?

Texas is our home. I don’t think I would have written the book without living here. Texas is a place with a strong sense of itself, and I like that. In The Passage, Texas has become its own country and is the last inhabitable place. Texas helps save the world. A lot of that has to do with the grit and can-do tone of the place. And the reason I like Houston is because it’s a place where you can do what you want. The Passage was a gigantic risk, it was a real shift in my writing life. Something new, something large—it could have failed. But the attitude of this place is “Sure, go for it. Go for broke.”