A writing competition which encourages scientists to author books that can inform and entertain non-scientists faces its most difficult decision to date.
The standard of writing has improved so much over the last decade that anyone of six books could win this year's Aventis Prize, says Professor Lord Robert Winston.
Winston is one of five judges who will decide in June which is the most accessible, informative and entertaining publication in 2003.
Managed by Britain's Royal Society, previous winners include Stephen Gould, Roger Penrose and Stephen Hawking.
Aventis Prize hopefuls:
In The Beginning Was the Worm, by Andrew Brown
A Short History Of Nearly Everything, by Bill Bryson
Magic Universe, by Nigel Calder
Nature Via Nurture, by Matt Ridley
Backroom Boys, by Francis Spufford
Mutants, by Armand Marie Leroi
The Aventis Prize itself is only worth just over $18,000 to the winner, but it usually guarantees a sales rush.
The titles put on Monday's shortlist cover subjects ranging from the origins of the Universe to genetic discovery.
Author Terry Pratchett, who sits on this year's judging panel, said the quality of the books was "noticeably better" than when he was first involved in judging the competition almost a decade ago.
Impressed by the "sheer readability" of the short-listed books, Pratchett described his guiding criterion for selecting the winner.
"It seems important to me that page one makes you want to turn to page two."
Fellow judge Daniel Glaser, a neuroscientist at University College London, said he was looking for "a book that non-scientists can enjoy and that addresses questions that people ask in their everyday lives that perhaps they can't easily find an answer too."