Harry Potter glasses and magic wands are a bit passé at bookshop events these days. Vampire teeth, dribbles of blood, white make-up and goth costumes are what younger readers are into when they dress up now, thanks to the extraordinary popularity of the teenage vampire novels that have been dominating the bestseller charts for months.

The start of 2009 will be remembered for the recession and the slump in retail sales. But in bookshops, the Twilight series of vampire novels for teens has bucked the trend and set a new record for book sales here.

American writer Stephenie Meyer's Twilight saga, about a contemporary young vampire in the US and the girl who loves him, has been a phenomenal success around the world and nowhere more than in Ireland, where her four Twilight books have been in the Top Ten Bestseller chart since Christmas. This has never happened before, even with Harry Potter. (In fact Meyer had five books in the Top Ten for a couple of weeks in January -- including the Twilight Movie Companion -- something that even JK Rowling never achieved and that set a record in the book trade here.)

The Twilight saga follows the adventures of Bella Swan, an American teenager who moves to a new town and finds her life is changed forever when she falls in love with a slightly strange boy called Edward Cullen, who turns out to be a vampire. Well over 300,000 Twilight books have now been sold in Ireland. And the books have become mandatory reading for teenagers not just here, but around the world.

So the blood may be flowing, but so too are the dollars, millions of them. The books are written by a 34-year-old Mormon woman from Phoenix in Arizona who said she was compelled to write them by a dream. Stephenie Meyer, an average American mom with small children, was a novice author when in 2003 she had a dream about an ordinary American girl in high school who falls in love with a boy sitting near her in class who turns out to be a vampire.

She can remember the dream with great clarity: "Two people were having an intense conversation in a meadow in the woods," Meyer says. "One of these people was just your average girl. The other person was fantastically beautiful, sparkly, and a vampire. They were discussing the difficulties inherent in the facts that A) they were falling in love with each other, while B) the vampire was particularly attracted to the scent of her blood, and was having a difficult time restraining himself from killing her immediately."

It was such a vivid image that Meyer felt compelled to start writing and the dream has now turned her into a global phenomenon, with the Twilight books translated into 38 languages and selling millions of copies worldwide. The film of the first book opened at Christmas, further boosting sales to the point where Meyer has been outselling Marian Keyes, Cecelia Ahern and even JK Rowling to become the biggest thing in books in Ireland since Harry Potter first waved his magic wand.

And it's not just Meyer. She is the biggest by far, but the new teenage horror genre now has a number of highly successful writers -- including Irish writers -- who are making serious money from the gore. It's a case of fangs for the millions.

Just last week, for example, Darren O'Shaughnessy, a young writer from Limerick, signed a deal with HarperCollins in London for a new series of vampire books. A report in The Bookseller, the bible of the book industry, mentioned the deal and casually added that the author already has sold "more than 15 million books worldwide and nearly 2.3 million in the UK."

With sales like that, he is probably earning more than John Banville and Sebastian Barry put together, so you may be wondering why you have never heard of him. O'Shaughnessy is better known as Darren Shan, prolific writer of horror books for teenagers, the early ones being written in his bedroom at home in Limerick. He now has a global following of devoted fans, almost all teenagers.

His new HarperCollins deal is for a four-book vampire series and a stand-alone fantasy quest novel and it also covers seven manga (Japanese comic) titles based on Shan's bestselling series, The Saga of Darren Shan.

O'Shaughnessy was born in London in 1972 but his family moved back here when he was six. Encouraged by his mother, a teacher, he started writing for adults but it was his debut novel for children, Cirque du Freak, which was his breakthrough book. It was the story of Darren Shan, who was an ordinary schoolboy until he and his friend got tickets to the Cirque Du Freak, a bizarre freak show featuring weird performers including at least one vampire.

This was a bestseller and was followed by other books in the Saga of Darren Shan series. O'Shaughnessy also has written a successful series featuring demons rather than vampires called The Demonata books.

His new series for HarperCollins will take him back to vampires. He told The Bookseller: "It may be related to either one of my existing series but I am not saying much about it as we are focusing on the last two Demonata titles (there are 10 in the series) which publish in May and October this year."

Another highly successful Irish author of teenage horror books is Derek Landy, who started writing while working on his family's vegetable farm near Lusk in north Co Dublin. Maybe it was looking at cabbages all day that did it, but he came up with the idea for a series based on a skeleton detective Skulduggery Pleasant and his sidekick, a young teenage girl called Stephanie.

It made such an impact that Landy got himself a million- euro contract and next month publishes the third Skulduggery book. Movies are being made of the books by both Shan and Landy so further riches lie ahead for both.

In the book trade no one knows how long the teenage horror craze is likely to last, but so far it is showing no sign of slowing down. David O'Callaghan, Children's Book Buyer at Easons, says that what is happening is brilliant for young readers. "I'm so excited -- even more so than when the Harry Potter books started to fly off the shelves. Combining elements of horror, romance, darkness and the supernatural, the teen horror/goth-lit genre allows the reader to connect emotionally and has captured imaginations worldwide.

"The books that fall into this category are truly gripping the nation and although this started off as a teen sensation, we can already see the average reader age spiralling upwards."

But why are teenagers going for these books in such big way?

Stella Paskins, Editorial Director of HarperCollins in Britain, has a theory: "I think the reason children appear to be veering to the dark side right now is because there's such a fantastic array of heroes portrayed who they can identify with. These heroes and anti-heroes are just like them -- kids who are facing up to demons (often literally) and fighting back. It can give a sense of empowerment that carries into their everyday life. And who doesn't enjoy being scared from the safety of their own room?"

Reflecting the huge interest in the genre, Easons last week announced a nationwide promotion which they are calling Welcome to the Darkside. The promotion features a list of about 40 teenage vampire/horror books, including all the top authors and titles, and offers three books for the price of two from the list for the next month.

The teenage vampire book craze has delighted teachers and parents, who have often struggled in the past to get teens to read and were worried that there might not be anything to fill the gap after Harry Potter. They should have had more bloody sense.