The numbers that delineate the Three Gorges project are so large they are difficult to conceptualise. The Yangtze River flows about 3,000km before it runs headlong into China's new Great Wall - 10 billion tonnes of concrete, poured in an arc about 40 storeys high and 2km long.

The resulting dam will have a discharge capacity 50 times greater than the Niagara falls and generate as much electricity as 18 nuclear power stations.

Deidre Chetham explains the multiple benefits that the dam will bring. The wild and unpredictable Yangtze will at last be tamed - none too soon, considering that about 500,000 people were killed by its flooding during the 20th century alone. The output of the dam's hydro-electric turbines will provide a pollution-free source of power for the industries of the 21st century's economic powerhouse.

This book, however, is intended to record just what will be lost. Chetham, executive director of Harvard's Asia Centre, began her love affair with the Yangtze 20 years ago when she was a travel guide on a Shanghai cruise ship that carried tourists up the river. Her affection for and familiarity with the history, the unique sites and the gorges' communities brings them vividly to life for those of us who will now never get to see them for ourselves.

The deluge accumulating behind the wall will drown more than 500km of starkly beautiful chasms, cliffs, peaks and valleys, and displace more than one million people. Chetham tranports her readers down into the rugged, inaccessible reaches of the gorges, where Beijingers are still considered suspicious foreigners and life has in many ways changed little in 1,500 years.

As she notes: 'Every rock or mountain along the Upper Yangtze is here for a reason that can be explained: a fairy turned into a rock, or someone's head was cut off and the dripping blood bored holes into the mountainside. The tales are part of the day-to-day life of the river ... so deeply ingrained that people of any age can tell you the most complicated stories of romances and battles of a millennium ago as if they had been there themselves, much the way some TV fans can recite the latest developments from a familiar soap opera.'

As the waters rise towards their peak in 2009, the inhabitants of the gorge will be relocated to an uncertain future in bleak, newly constructed townships on the treeless hilltops surrounding the new waterline.

Chetham summarises the concerns of those opposed to the scheme. Given its cost, both in dollars (official budget $200 billion) and destruction of environment, history and society, one can only hope the critics are wrong and that it does not turn out to be the greatest white elephant in Asian history.