The cover photograph is the saddest part of this sad book. Gracefully curved in the water, showing his unique long bill, is Qi Qi, one of the very few Yangtze River dolphins (or ‘baiji’) ever photographed. Now dead, Qi Qi was a rare captive.  You will probably never see another, in the Yangtze or, like Qi Qi, in a Chinese reserve. As Samuel Turvey observes in his informative, comprehensive – and angry – study, in the past 500 years ‘only four other entire mammal families have also died out’.

One of the few species of river dolphin, the baiji has a pedigree stretching back twenty million years in the Yangtze Basin, and is described in ancient Chinese sources. Turvey, a palaeontologist at the Zoological Society of London, has spent a good deal of his young life trying to see