Brown said that students would soon be able to carry all their books with them and ensure that they always had the most up-to-date edition. Eventually, he thought, the lower costs of publishing e-books would encourage publishers to take risks on lesser known authors. "The effect of this is that there will be more books in print and more choice for readers," he said.
The Reader is expected to go on sale in America in April at between $300 and $400. It should arrive in Britain soon afterwards.
Owners will be able to buy books from Sony's online store, download them to a computer and transfer them to their Reader. They will also be able to download free any books that are out of copyright.
The gadget is designed to be held in one hand and the pages are "turned" at the press of a button. It can also display drawings and pictures and the text can be enlarged up to 200 per cent to make it easier for readers with poor sight.
Sony says the rechargeable battery will power 7,500 page turns between charges.
The page is made from millions of tiny capsules, suspended in a transparent liquid coating a plastic film.
The capsules contain positively charged white particles and negatively charged black ones. Depending on what type of charge is applied to the page, the white or black particles move to the surface of the capsule, forming images.
The first version can display text and pictures in black and white only, but a colour model is likely to follow.
Ron Hawkins, a marketing executive at Sony, said: "In recent years, millions of people have become comfortable downloading and enjoying digital media, including e-books, but until now there has not been a good device on which to read.
"Our research has shown that people are looking for a device designed exclusively for immersive reading. The Sony Reader, with its electronic paper display, thin format and extraordinary battery life, fits the bill." ( finished)
