We caught up with bestselling author Justin Cronin, whose novel The Passage depicts a post-apocalyptic world of psychic vampires. He told us what makes his vamps tick, and also what's in store for the Ridley Scott-produced Passage movie.

In the video above, Cronin does a great job breaking down what makes his vampires fascinating: He's taken all the myths about vampires and tried to make them as scientifically plausible as possible. In his universe, vampires are the result of a medical experiment with longevity. Infected with a virus that sends the thymus gland into hyperdrive, his vampires have super-immune systems and seeming immortality. Plus, they hate seeing themselves in mirrors.

The formula works: This literary author's first effort at writing popular fiction has been on the bestseller list since it came out a couple of months ago.

Justin Cronin explains his vampires in "The Passage," and drops spoilers for the next book

We also talked to Cronin about how The Passage, which is set mostly in a few remote, post-apocalyptic towns, is about small town life. He said he did that in order to focus readers' attention on his characters. Cronin told io9:

If I was going to place these characters in a great deal of jeopardy and send them across the continent, where many would die, I had to earn the right to do that to them. And you earn that by giving them the full dignity of their humanity. Who are you? You live in a town you have friends and connections and associations. [In my book] it's a medieval town – life is short, brutal and brief. The meaning of having a child isn't sentimentalized. Marriage is a big question. And yet the arrangement of the community is familial, domestic. I had to do some world building. A lot of time [books like this are] about technology and physical circumstances. Well [my characters] have very little technology and the physical world is simple. So I had to create this social matrix, this lifeboat, which has continued with stability through an apocalypse. These people have found a way to exist socially that's resilient.

For the most part what's left are the good people. Unconsciously that was what I was advocating for. In this particular community, which was based on domestic patterns, they survived. I'm holding that up as a virtue. It's a source of their courage too. You gain your courage via your connection to other people.

Given that his book mixes the apocalyptic with elements of the biotech thriller - and even includes a great train robbery - I wondered what Cronin's own appetite for science fiction was like. Here's what he said:

My pop culture influences are mostly from the 1960s and 70s. I pre-cyberpunk science fiction. At that time, there were two major strands in speculative fiction: one was optimistic and one was pessimistic. The conquest of space was optimistic. You had things like 2001. But the dark strand was always an expression of anxiety over the threat of nuclear annihilation. The Cold War created anxiety so tremendous that it pushed all other anxieties off the table. You learned that there was this thing hanging over us. And there was the crazy dark beauty of mushroom clouds. Those were the influences.

I remember going to a Planet of the Apes film festival at the local theater. I was really struck by the second one, Beneath the Planet of the Apes, where the entire world blows up. Also, I'm a huge fan of The Omega Man, and I watched a lot of the Logan's Run TV series.

So what's next? The Passage is the first in a trilogy, all of which could become movies if the movie version of The Passage pans out. Here's what Cronin says is coming next (spoilers!):

The next two books each go back to Year Zero at the outset, to reset the story, and to deal with something you didn't see and didn't know was as important as it was. It's not a linear quest story, which I would find dull and plodding. With each book, you need to have the narrative terms reestablished with fresh elements. Also, if you didn't see [a character] die, they're not necessarily dead. There's a big cast in the first book, and plenty of unresolved stuff. I will resolve it by the end. [Early vampire character] Anthony Carter? No, not abandoning him.

In second book, you go back to what happened in Denver after the outbreak took place. The story will resume in that location a few days after breakout. So you can see another angle on what occurred and certain elements will affect our band of heroes 100 years in the future. It will be called The Twelve - and it's not who you think.

As for the movie:

[Gladiator scribe] John Logan is writing the script and we've talked about it a lot. [The movie is just] the first book, but I've mapped out the next two books, and they know what comes next. We're planning on three movies, but I'm realistic. Though hopeful!

The Twelve will be out in 2012.