Being an account of the Great Leap Forward famine. Which means that it is, often enough, not pleasant reading. It is, however, thorough and extensive in detail.
It opens with an overview of famine in China, the Communist takeover and plans for the peasantry, and an account of the infamous Ukrainian famines, which he presents as the closest analogue to the Great Leap Forward.
It then goes through the collectivizations and the nonsense science that led to the famine. Ludicrous farming practices. The rejection of the notion of inherited traits as "fascist." Absurd claims of cross-breeding: tobacco with cotton to produce red cotton. Even when the cross-breeding was feasible, the results were not good; Chinese pigs, after cross-breeding with Soviet pigs that had larger litters, had the litters without having milk enough, so all the piglets died. Fantastical high claims of yields -- even in the famine, the government exported grain, and stored grain in places where it unquestionably rotted, uneaten.
Then into the famine itself. After an overview, it discusses the different conditions in various regions, and prison camps and cities, and the physical effects and the cannibalism that ensued. Some families, having decided to starve a daughter, would trade the corpse with a neighbor so they ate the neighbor's daughter rather than their own; the famine was particularly hard on girls, with his estimate being about a quarter of the victims, and telling how some villages had dozens of men who never married for the lack of women of the right age.
Mao's hearty resistance to the notion of famine, the cracking of his power that let some Communists act to stop the famine -- and the Cultural Revolution, which, he argues, was aiming precisely at those who stopped the famine and saved lives by the thousands. (He also argues that the Stalinist purges were targeted at those who stopped the Ukrainian famine. It's a good argument insofar as I can judge it.)
Oh, and here's an alternate history suggestion for any writer who wants to run with it: Taiwan heard enough to make them think of trying to invade, but they never managed to swing American support. Becker wrote that it might really have been possible. So, if they decided to forgo the American aid, or got it. . . .