A reader writes in: "I am interested in the subject of the US Army Observer Group in China 1945-1947. In particular, I would like any information about Henry Whittlesey, who was a member of that group and went missing/died and his body never recovered. He must have done something heroic to have Mao (Zedong) have a building dedicated to him with his name on it."

"Would Dr (Andrew) Lam be able to shed light on this, given his research in writing Two Sons of China?"

The US Army Observer Group in China, also known as the Dixie Mission, was the country's first attempt to establish official relations with Mao's Communist Party of China and the People's Liberation Army, who were holed up in the northern mountain city of Yenan (Yan'an).