IN 1979, SOON AFTER The Hitchhiker’s Guide to the Galaxy was published, Douglas Adams was invited to sign copies at a small science-fiction bookshop in Soho. As he drove there, some sort of demonstration slowed his progress. “There was a traffic jam and crowds of people were everywhere,” he recalls. It wasn’t until he had pushed his way inside that Adams realised the crowds were there for him. Next day his publisher called to say he was number one in the London Sunday Times best-seller list and his life changed forever. “It was like being helicoptered to the top of Mount Everest,” he says, “or having an orgasm without the foreplay.”

Hitchhiker had already been a cult radio show, and was made in both television and stage versions. It expanded into four more books that sold over 14 million copies worldwide. There were records and computer games and now, after twenty years of Hollywood prevarication, it is as close as it’s ever been to becoming a movie.

The story itself begins on earth with mild-mannered suburbanite Arthur Dent trying to stop the local council demolishing his house to build a bypass. It moves into space when his friend, Ford Prefect—some have seen him as Virgil to Dent’s Dante—reveals himself as a representative of a planet near Betelgeuse and informs Arthur that the Earth itself is about to be demolished to make way for a hyperspace express route. They hitch a ride on a Vogon spaceship and begin to use the Hitchhiker’s Guide itself—a usually reliable repository of all knowledge about life, the universe and everything.

Adams’s creativity and idiosyncratic intergalactic humour have had a pervasive cultural influence. The phrase “hitchhiker’s guide to . . .” quickly became common parlance, and there have been numerous copycat spoof sci-fi books and TV series. His Babel fish—a small fish you can place in your ear to translate any speech into your own language—has been adopted as the name of a translation device on an Internet search engine. He followed up his success with several other novels as well as a television programme, and a book and CD-ROM on endangered species. He has founded a dot-com company, H2G2, that has recently taken the idea of the guide full circle by launching a service that promises real information on life, the universe, and everything via your mobile phone.