Mr. Yang's father would die within three days. Yet it would take years before Mr. Yang learned that what happened to his father was not an isolated incident. He was one of the 36 million Chinese who succumbed to famine between 1958 and 1962.
It would take years more for him to realize that the source of all the suffering was not nature: There were no major droughts or floods in China in the famine years. Rather, the cause was man, and one man in particular: Mao Zedong, the Great Helmsman, whose visage still stares down on Beijing's Tiananmen Square from atop the gates of the Forbidden City.
Why would a book that documents the "single greatest atrocity of the 20th century" be allowed in China, a country with a repressive government?
It also needs a certain number of people who understand the full truth about the Maoist system so that the party will never repeat its mistakes, even as it keeps the cult of Mao alive in order to preserve its political legitimacy. That's especially true today as China is being swept by a wave of Maoist nostalgia among people who, Mr. Yang says, "abstract Mao as this symbol of social justice," and then use that abstraction to criticize the current regime.