A search for whales in the Sahara

Here is a lovely book, beautifully and freshly written, that few could resist reading, though one must brace oneself to ignore occasional brazen Bronx heresies and the rare but shameless transatlantic belch (what can one do with "had gotten"?). Apart from that, Carl Zimmer's smooth and easy style is a relief from Stephen Jay Gould's scholarly but sesquipedalian cascades. It is so clear for the newcomer to genetics that it makes our own Steve Jones seem obscure by comparison. In episodes such as Jenny Chack's search for tetrapods on the cold, barren hills of Greenland, the narrative matches a fine novel in excitement. And this is what the book is all about, as its sub-heading indicates.

Most of us are accustomed to what has become known as microevolution - the almost infinitely slow, creeping, step-by-inscrutable-step of Darwinian evolution. But this book will change the way you think about our position within the life process, the billion-year leap from fish to the acutely sentient dry-land bipeds we have become, conceiving great cathedrals, wondering about vacuum energy and groping for the stars.

Zimmer reveals how the descendants of one lineage of marine life took to dry land - or at least to marshland - and with remarkable evolutionary speed produced reptiles, birds and mammals, including us, and then in another wave rushed back from where they came to become the highly intelligent submarine forms of life we know as whales and dolphins. He has taken advantage of every scrap of new knowledge - and there is so much of it that even the palaeontologists themselves have a job to keep up with what they are discovering. "Part of the problem," Zimmer tells us, "lies in the fact that many of the recently discovered fossils turned up so suddenly that their discoverers have had to stumble to conferences with carousels full of slides so new they haven't seen the pictures themselves."

Those of us who long ago wearied of seeing television pictures of the endless fratricidal killings in Afghanistan, the excesses of fanatics like the Taliban Muslims and the horrors of land-mine mutilations will be cheered by Zimmer's account of unconcerned little men who were tottering about throughout all this looking for fossil whales, or bits of them, and finding them too. Could human motivation be more diverse than that of the Muslim Taliban fanatics and of American palaeontologists scratching among arid rocks in search of bits of ancient whales, all at the same time?

Like so much of palaeontology, whales in deserts, even the Sahara, seem ridiculously improbable but they are there, and Zimmer's delightful account makes it all so real and convincing.

His description of the work of one of his heroes, Phillip Gingerich, searching for whales in the Sahara, is as entertaining as any of the exploration of the Dark Continent by the great Victorians. Whether describing the graveyards of leviathans in deserts or the dusty, crumbling bits and pieces of fossilised bone abandoned in university drawers a century ago by scholars who could not have understood the importance of what they had found and were treasuring, Zimmer constantly provides us with something new and surprising.

It is wicked, I know, but I have the habit of turning over the corners of pages whenever I chance upon something unexpectedly interesting, exciting or informative. Zimmer's At the Water's Edge quickly became the most dog-eared book on my shelves.

Harry Miller is a fellow of the Zoological Society.