Amid the avalanche of summer reading crashing on to my desk falls another hefty tome about China's re-emergence as a global power. The theme is familiar: the present century will belong to Asia in general and to China in particular. The book's title, When China Rules the World, permits none of the doubts and vacillation about the future course of events that often afflict this columnist.

By unhappy accident, publication has coincided with the most serious unrest since the Cultural Revolution, in China's Xinjiang province. Scores, perhaps hundreds, have been killed in ethnic clashes. Hu Jintao, the Chinese president, this week felt obliged to cancel his appearance at the Group of Eight summit in Italy to fly back to Beijing.

Skipping a gathering of some of the world's most powerful politicians was no small thing for the leader of a regime that that places a high premium on the image it shows the rest of the world. Yet it was also a reminder that China's politicians are rarely quite as confident as western observers about their country's destiny. In my experience, the west's awe is as often as not matched by China's anxiety.