Professor Richard Dawkins took part in a campaign decrying religion with slogans on London buses. Photo / AP

Professor Richard Dawkins took part in a campaign decrying religion with slogans on London buses. Photo / AP

Richard Dawkins might be making progress.

The English scientist and best-selling author has for years been a fearless critic of organised religion and makes no bones about his feelings about believers.

Dawkins is one of the big name attractions - if not the biggest - at next year's New Zealand International Arts Festival. He intends to devote his address in March to his new book, The Greatest Show on Earth, The Evidence for Evolution, which has been on the New York Times best-seller list for weeks.

He wrote the book, he says, to fill a rather large gap which he felt was missing from his previous popular science works - namely "the evidence for the fact of evolution".

The Greatest Show on Earth , Dawkins' 10th book and a lavish tribute to Charles Darwin, lays out in 400-odd pages details - from the fossil record to molecular physics to recent genetic discoveries - which state categorically that we are all relatives, no matter how distant, of every other living thing.

Along the way he explains why a particular moth has a tongue that stretches more than 20cm, how wild foxes can turn tame and doglike in a few short generations, why there is no such creature as a "crocoduck" - a jibe at creationists.

He throws in for good measure everything from dogs, chimps, the so-called 'missing link' and even tree rings.

He finds evidence for evolution at every turn. Those goosebumps you experience when things get scary - they derive from hair-raising reactions to fear in animals from primates to dogs.

"Evolution is a fact," he states, with the evidence "at least as strong as the evidence for the Holocaust, even allowing for eyewitnesses to the Holocaust".

And: "It is the plain truth that we are cousins of chimpanzees, somewhat more distant cousins of monkeys, more distant cousins still of aardvarks and manatees, yet more distant cousins of bananas and turnips ... continue the list as long as desired."

Not that Dawkins expects the "history deniers" - his term for people who prefer the creation story - to be persuaded by his account, which was partly driven by his determination to challenge the depth of attachment to creationism.

In the United States, the Gallup polling organisation has consistently found that more than 40 per cent of Americans totally deny evolution, whether or not it is guided by God.

"The implication," writes Dawkins, "is that they believe the entire world is no more than 10,000 years old. As I have pointed out before, given that the true age of the world is 4.6 billion years, this is the equivalent to believing that the width of North America is less than 10 yards [9m]."