A horror fiction series aimed at the under-12s has become a publishing phenomenon in the United States. Goosebumps books, which are also available in Britain, are selling 4 million copies a month worldwide, rivalling the sales of adult thrillers.

Some parents and teachers say they are glad to see children - who usually demand the latest Disney cartoon, video game or action figure - with their noses in a book. Others argue that Goosebumps stories show questionable grammar, plotting and taste.

The success of the series is partly due to publisher Scholastic, which has longstanding connections with school book clubs and other child market outlets, and has published other best-sellers along with a range of children’s magazines. The books are published in Britain by Scholastic UK.

The 130 million Goosebumps in print include titles ranging from Welcome to the Dead House and Monster Blood. Their author, Robert Lawrence Stine, joked in a rare interview recently that there are only five plots, including the mummy, the haunted house and the werewolf. Sales worth $450 million (Pounds 300m) have made millionaires of Stine and his wife, Jane, who is his business manager.

“Kids like the fact that there are one after another after another,” said Jan Kristo, a professor of education at the University of Maine. “It’s the kind of things kids are used to seeing on videos. They are a fairly easy read and you don’t have to think about them too much.”

Professor Kristo is wary of the books’ mass-produced feel. “But if we try and censor them, they are going to read them anyway,” she said. “The important thing for adults is whether they lead kids to good books.”

Goosebumps first appeared in 1992 and began to take off about a year later, said a Scholastic spokesman. Mr Stine, who writes as RL Stine, has already produced a successful teen series called Fear Street.

Children collect the Goosebumps books in a craze similar in scale to Cabbage Patch dolls and Power Rangers, and it has taken hold with very little advertising.

Only now have they spawned spin-offs, including a CD-Rom, television show and board game. Mr Stine told recently of being mobbed by 5,000 children when he turned up for a book signing in Virginia.

Scholastic is a 75-year-old concern but only began producing its own books in the Eighties, including other well known series like The Babysitters Club (recently made into a feature film) and The Magic Bus.

But Goosebumps has apparently broken the mould by appealing to boys as well as girls. Other publishers are now stepping in with their own horror offerings for children.