In practice it never quite worked, and there is a tension in the book between the idea of the Great Helmsman as strategic genius and his foreign policy failures. One reason he supported the North Korean attack on the South in 1950 was his conviction that the US would not intervene, and in 1969 the Russians declined to take their lesson quietly: their response was to bombard the Chinese side of the frontier so intensively the CIA said that from the air it looked like a moonscape, and sound out international opinion about a strike on China’s nuclear installations in Xinjiang province. Not too clever. To show that China could never be intimidated, Mao had mocked nuclear weapons as paper tigers, but he would not have been happy to see his own go up in flames.