TALK about ambition. Science Fiction writer Stephen Baxter treads where only fools or angels dare to go, with a massive novel spanning 565 million years of human evolution.

He begins 65 million years in the past, when our ancestors were tiny, shrew-like creatures scuttling around in the shadow of the dinosaurs. Then a giant comet struck, the dinosaurs were wiped out - and the little creatures inherited the Earth.

Baxter follows our ancestors down the aeons, as the continents shift beneath their feet and new species of plants and animals rise and fall around them.

He does it in a series of what amount to short stories, each a few million years apart, each following the life of one of our ancestors; a squirrel-like notharctus 50 million years ago; a monkey-like ancestor 32 million years ago: a chimp-like predecessor five million years ago.

It is hard going in the early stages - difficult to empathise much with a squirrel. But, as the book reaches our immediate ancestors the hominids, it picks up, following the human story through the first upright apes to walk the plains of Africa; Neanderthal man; the coming of modern man and his journey out of Africa.

There's a brief stop in ancient Turkey, where farming was first practised, a visit to Rome in the dying days of Empire, and then next stop is the year 2031 and an environmental conference called in an attempt to save the world from overcrowding and pollution.

The story doesn't end there, however. Following an apocalyptic war, humans are almost wiped out, the few survivors wild, uneducated children.

The relentless pressures of evolution continue to work. A thousand years in the future, their descendants are savages who have lost the power of speech. Thirty million years in the future, the descendants of human beings are huge, ponderous creatures with massive ears, fur covered bodies and immense teeth for grinding dense foliage. Not a shred of the intelligence that led humanity to destroy itself remains.

An astounding achievement, that offers a bleak warning and a true perspective on our place in the scheme of things.

Updated: 08:53 Wednesday, November 19, 2003