The world's largest book fair on Tuesday hailed the Internet as a welcome ally in the international expansion of publishing.

Book sales have led the electronic retail revolution on the Internet, in turn giving a welcome sales boost to the book, one of the oldest technologies in the world.

The Frankfurt Book Fair, which this year has attracted 6,600 publishers from a record 113 countries, has eagerly embraced the cyberspace revolution - one in four exhibitors at the last fair of the millennium now offer electronic publications.

Internet companies have become stock market stars, with Amazon.com boasting sales of just over $1 billion and a stock market valuation that has topped $30 billion.