Vampires and deadly spiders are the stuff of teenage schlock horror but 29-year old Darren O'Shaughnessy revels in them. Never heard of him? Your teenage son or daughter has, and so have 11 and 12-year-olds who like to read ahead of themselves. Living at his parents' west Limerick home, O'Shaughnessy is producing a series of books centred around a character who has a thinly-disguised version of his own name, Darren Shan, and who becomes a vampire's assistant. Like a cliffhanger TV series, each book ends with a "to be continued" reminder.

He is also using the pseudonym of Danen Shan, giving an extra sense of realism to the novels for thousands of fervent irnaginations. "I get kids e-mailing me all the time, asking me if it is really true." So far, he has written four novels, with the fifth, Trials of Death, due in October and another 15 or so planned over the next seven years. "I know how it finishes up. There are still lots of blanks to fill in in the second half of it."

In the era of Buffy the Vampire Slayer, the adventures of the teenage Darren Shan have struck a chord with both male and female readers. "Girls have really taken to it in a big, big way," he says. Warner Bros sat up and took notice when they received a copy of Cirque du Freak, the first in the series, from O'Shaughnessy's agent, Christopher Little. Little also acts for J.K. Rowling, the leader in young readers' fiction with her Harry Potter series, and she, in turn, endorsed Cirque du Freak, describing it as compelling. In fact, the whole Harry Potter phenomenon has buoyed up teenage fiction. "Harry Potter raised the whole thing of children’s books. Before that, the perceived wisdom was that there is not big money in children’s books. If you were a good children’s writer, you would make a steady income every year but you did not get big advances up front."

He is still living modestly. The bungalow home, on the same site in Pallaskenry where his great-grandfather grew up, has hens out the back. O’Shaughnessy gets around on his bicycle, admitting that, yes, he must apply for a driver's licence. He has retained the boyish looks of his readership and nurtures their loyalty through his website, www.darrenshan.com and through a rapport with the kids in Askeaton National School where his mother teaches. He spends an hour a day responding to e-mails, sometimes to fans who want to ask him out. "There was a lot of publicity when the first book came out. When you work on a series, reviews tend to drop off. There is not as much of a hullabaloo when each book comes out. But what is happening is the reader base is growing all the time."

He leads a quiet life most of the time, socialising in Limerick maybe once a week but sometimes going for months without a visit. The people he grew up with have mostly moved away. "I am quite reclusive. I tend to sort of go my own way. I do have friends and I go to London as well. I have cousins and uncles that I like to meet up with but most of the time I stay in." Born in London, he moved to the ancestral home at the age of six, went to the local schools, played some hurling along the way and did a degree in sociology and English back in London. He worked for a while with Chorus, the cable television company, before devoting himself full time to writing.

He writes for up to six hours a day, preparing a rough draft and editing the script several times before being satisfied with the result. "When you have been writing for a few years, you find that it's not the quota that is the hard thing, it's saying what you want to say. I can write 10 pages no problem. I go through them later on and maybe I cut eight or nine of those out. I always think it is good to get a first draft done. When I'm writing a first draft, I don’t think about the quality."

Fantasy and film are ever present. The front living room has a Conan the Barbarian replica sword leaning against the fireplace, a 55-inch television, and about 2,500 films and TV series such as Cracker, The X-Files and The Sopranos, on video and DVD. "I watch films more than TV. When it comes to film I will watch anything." Buffy, however, has barely had a look in. He saw the original film but ignored the series.

He is coy about giving details of the five-figure sum he received for selling the option rights to his first three books. It will become a seven-figure sum if David Heyman, producer of Hany Potter and the Sorcerer's Stone, decides to make a film. "So far, there has not been any script produced ... I don’t think," O'Shaughnessy says. He admits to doing "very well" financially as the publishing rights get sold in the US, Japan, China and Germany [among others]. "It has done very well in Japan. It did a first print of, I think, 50,000. They have gone to a second print of 40,000."

He is not worried about a film version bastardising his stories beyond belief " la la Captain Corelli’s Mandolin. He points to the "terrible" films based on Stephen King novels. "It's a different industry. Raymond Chandler said that back in the 1940s. Somebody said to him, ‘Are you concerned with what Hollywood has done to your books?' He said, ‘They have done nothing to my books. Those are my books on the shelf.' Most people who go to see a film are not going to read a book anyway."