Tremendous story, a well researched personal destiny as well as an introduction to the geopolitics of the last century. One takeaway is how obviously poisonous substances (Agent Orange) were sprayed over large swathes of land in Vietnam and elsewhere for military tactical purposes, causing medical conditions of varying severity for 3 out of 4 million people affected in Vietnam. It was heavily criticized at the time, as it could be suspected of being harmful to humans as well as the forests and crops that were targeted, but it did not stop the program. [0].
"The government of Vietnam says that up to four million people in Vietnam were exposed to the defoliant, and as many as three million people have suffered illness because of Agent Orange" according to linked Wikipedia article.
R.I.P. Bùi Tường Phong.
[0] https://en.wikipedia.org/wiki/Agent_Orange