Welcome to a secret world: dial the special number in Detroit and you have arrived at the "Forbidden Zone". This is strange territory - a menu offers passwords to gain access to government computers, a list of credit card numbers and what every good citizen needs to know how to make ....... nitro-glycerine!

Not tempted? Well, what about "Dragonfire"? Here phone freaks are offered the access codes of telephones companies, enabling free calls to be made. Hackers may also acquire the numbers and passwords for university computers or corporate mainframes.

For this is the world of the underground bulletin board. Run by precocious youngsters who possess an alarming knowledge of computer security systems, and how to get round them. Unfortunately, their language and grammar indicate other studies have been neglected. The numbers of these boards are closely guarded, their security formidable and would put some large businesses to shame.

One reporter, Richard Sandza, managed to penetrate this secret world using the undercover name "Montana Wildhack". He then wrote an article in "Newsweek" about the boards. Furious about the exposure, the hackers' revenge was swift. Richard found his car licence had been revoked, his social security records altered and his credit card numbers posted on Bulletin Boards throughout the country, inviting use.

So remember, the next time you get a bill for something you haven't bought, it may not be a mistake...

Jack Warburton, EUG #2