No armchair theorist, Dr. Lifton conducted more than 70 interviews for “Death in Life.” For “The Nazi Doctors: Medical Killing and the Psychology of Genocide” (1986), he interviewed more than two dozen SS physicians and others, as well as numerous survivors of the death camps. The title of Dr. Lifton’s memoirs was “Witness to an Extreme Century” (2011). Bearing witness to the psychic consequences of extreme events was his life’s work. In addition to Hiroshima and the Holocaust, Dr. Lifton wrote books about Chinese thought reform (more commonly referred to as “brainwashing”), Mao Zedong, and the Chinese Cultural Revolution, the...