As you may have heard, Pemberley has been overrun by zombies.

The news was announced in the recently released novel "Pride and Prejudice and Zombies," which recounts the struggle of Elizabeth Bennet and her sisters to simultaneously annihilate the undead invading their idyllic community and to marry well.

Were it just the zombies, the Bennet sisters would surely triumph, armed as they are with advanced weaponry knowledge and Shaolin martial arts training. Unfortunately, however, aliens, vampires, robots and dragons are also about to descend on the village.

What is it about Jane Austen?

Her works have inspired unauthorized biographies, cookbooks, television miniseries, Jane Austen book clubs, a book about a Jane Austen book club, and a movie about the book about the Jane Austen book club. And now, having exhausted every Austen story line humanly possible, authors and screenwriters are turning to what is inhumanly possible.

The glowing reviews of "Pride and Prejudice and Zombies" prove that the public will accept anything in the Jane Austen spinoff genre. The question is why these silly, campy things work so well.

"It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains." The first half of that line is Austen's; the second half is California author Seth Grahame-Smith's. That's pretty much how the whole book reads: The Bennet sisters are minding their own business when all of a sudden reanimated human corpses stagger into the setting.

Consider the famous ball scene, in which Elizabeth first meets the haughty Mr. Darcy. Darcy says rude things, Jane and Mr. Bingley dance, and then, "Unmentionables poured in, their movements clumsy yet swift, their burial clothing in a range of untidiness. Their flesh was in various states of putrefaction. ... As guests fled in every direction, Mr. Bennet's voice cut through the commotion. 'Girls! Pentagram of Death!' "

"In the original 'Pride and Prejudice,' there are so many things suited to make it into a horror," Grahame-Smith insists. His book is 80 percent original Austen text — he's simply woven a complementary monster story line into the existing romance. For example, in Austen's work, Grahame-Smith says: "There's a regiment of soldiers camped out in Meryton for apparently no reason. It's not a big leap to say that the regiment is there to burn coffins and kill zombies."

Others agree with Grahame-Smith's horror-setting assessment. In "Pride and Predator," a screenplay recently picked up by Rocket Pictures, Austen's beloved characters are terrorized by a ruthless alien who lands on Regency-era Earth, then begins mass slaughter.

"We've seen Will Smith and Arnold Schwarzenegger and Tom Cruise take on aliens," screenwriter Will Clark writes in an e-mail from London. "It's time to see if the likes of Judi Dench, Alan Rickman or Emma Thompson can handle themselves," too.

Austen herself becomes the monster in "Jane Bites Back," a novel by Michael Thomas Ford that will be published in 2010 by Random House. In it, Austen is a frustrated vampire and bookstore owner. "She's been middle-aged for 200 years, which is not making her happy," Ford says. "We've been calling it 'Bridget Jones' meets 'Dracula.' "

Charlotte Bronte also has received some of this dubious adulation — check out Sharon Shinn's "Jenna Starborn," aka "Jane Eyre" on a remote, futuristic planet — but Bronte's works, and those of other beloved authors, haven't been morphed and mutated to half the extent that Austen's have.

(By the way, we're not even getting into the spinoffs that exist in the fan world: "Pride and Prejudice and Dragons" is the name of one multichapter work on FanFiction.net; in "The Musician and the Millionaire," Elizabeth Bennet becomes a contestant on a dating show only to learn that the prized Darcy is, alas, a bloodsucker.)

Part of the reason for that is the bottom line. "I was talking to my agent one day," says Ford, describing the origin of "Jane Bites Back," "and one of us made the comment that the only things that seem to be selling are Jane Austen and vampires."

Part of it is the bordering-on-fanatical relationship some people have with "Pride." (See: "Lost in Austen," a new movie in which a modern woman wakes up and realizes she has become Elizabeth Bennet.) "Pride and Prejudice and Zombies," impossibly, works — in part because of story lines like the one developed for Charlotte Lucas. In Austen's "Pride and Prejudice," Lucas is a pragmatic soul who marries for financial security. In Grahame-Smith's book, Lucas gradually transforms into a zombie, though no one notices.

The beauty of this side plot is that it's true to Charlotte's resigned character. Austen drew her so completely that we know she would bear her zombitude with quiet grace and that her idiot husband would miss it entirely.

The completeness of Austen's characters is what allows them to be transported successfully to a variety of settings, from Middle Earth to outer space, says Susan Allen Ford (no relation to Michael Thomas Ford), editor of the Austen journal Persuasions. Austen's use of language helps, too. "People in this period never really said what they meant," says Grahame-Smith. Austen's characters are simply too mannered to gush about their feelings. As a result, "there's a level of complexity and subtext that's at work through her novels," says Susan Ford. Readers must fill in the gaps for themselves.

But for a Jane Austen fan, the gratifying aspect of reading "Pride and Prejudice and Zombies" is not the comic bloodthirsty additions, but rather how they highlight the humor that already exists in the original "Pride and Prejudice." Austen was funny — something that's easy to miss if you get too caught up in the romance and cravats. Reading "Zombies" means discovering that half of the things you're laughing about were written 200 years ago by Austen herself.

As for Grahame-Smith, he reportedly has signed a deal for two more "historical" books, including "Abraham Lincoln: Vampire Hunter."