Who would have thought the Universe is made of string?

Professor Lewis Wolpert, chairman of the judges

With a cash prize of �10,000, the Aventis has become the world's most prestigious science book award and guarantees huge sales. Not that Professor Greene needs the marketing support - his account of the quest for the "theory of everything" has walked off bookshelves around the world.

The Elegant Universe (Jonathan Cape) centres on one of the most ambitious theories ever proposed: Superstring Theory.

This proclaims that all the wondrous happenings in the Universe are reflections of one grand physical principle and manifestations of one single entity: microscopically tiny vibrating loops of energy, a billionth of a billionth the size of an atom.

Critical acclaim

In his book, Greene uses everything from an amusement park ride to ants on a garden hose to explain the beautiful yet bizarre realities that modern physics is unveiling.

Professor Lewis Wolpert, who chaired the judges, announced Professor Green as the winner at a ceremony in London's Science Museum.

"This is science as magic," he said of The Elegant Universe. "At last somebody's managed to explain a new fundamental theory of everything. Who would have thought the Universe is made of string?"

Critics at the Sunday Times said of the book: "Not since the extraordinary success of A Brief History of Time [by Stephen Hawking] has a scientific book caused such a stir.

Compelling works

Professor Brian Greene told BBC News Online that he was surprised to win. He said that when he started The Elegant Universe he kept the project a secret.

"I didn't tell anybody I was working on the book because if it didn't work out I could just throw it away and not be embarrassed, and nobody would know.

"But as I continued to write it, I found it was falling into place and I felt it was accessible. It was a learning process for me, but by the end I felt I'd been able to get a sense of what it is that helps people understand abstract ideas."

"The other books are very great and compelling works, and I was really honoured to be part of that community and to win is very gratifying."

"An eloquent sweep through the history of modern physics and cosmology."

 Professor Greene took your questions on the "theory of everything" in a BBC News Online Talking Point On Air programme last August. Click here to watch the show

Others shortlisted for the prize were:

The White Death by Thomas Dormandy (The Hambledon Press)

Author: Consultant pathologist who has spent many years researching and writing on the impact of TB on society, art and literature.

In brief: The long and ultimately successful battle against TB.

A Brief History of the Future by John Naughton (Weidenfield and Nicolson)

Author: Lecturer in systems at Open University, fellow of Wolfson College, Cambridge, and award-winning internet columnist.

In brief: Origins of the internet.

Genome by Matt Ridley (Fourth Estate)

Author: Doctor of zoology and chairman of the International Centre for Life. Genome is the third of his books to make the shortlist.

In brief: Guide to human genetics.

Children of Prometheus by Christopher Wills (Allen Lane)

Author: Professor of Biology at the University of California in San Diego and award-winning populariser of science.

In brief: Humans are evolving faster than ever before.

Time, Love, Memory by Jonathan Weiner (Faber & Faber)

Author: Former editor of US-based magazine The Science and author of the Pulitzer-winning The Beak of the Finch.

In brief: How scientists are getting closer to the links between genes and behaviour.

The winner of the Junior Prize was the DK Guide to Space by Peter Bond (Dorling Kindersley).