IM.G. Sheftall's oral history of the dawn of the nuclear age, Hiroshima: The Last Witnesses, is published this month. The book is based on interviews Sheftall, a historian and professor at Shizuoka History, conducted over eight years with dozens of hibakusha survivors and others in Japan, Korea, and Taiwan. Sheftall, who previously wrote an acclaimed oral history of wartime kamikaze pilots, said he was prompted to take on his latest project after an epiphany during U.S. President Barack Obama's historic visit to Hiroshima in 2016. Over 545 pages, the book plunges into the horrors of the bomb, its victims and its occasional ironies, among them that a Japanese scientist, Hideki Yukawa, had indirectly helped the development of the bomb by being the first to mathematically show the existence of strong nuclear forces in the universe.

Sheftall notes that while Hiroshima was considered a military target, most of its residents were too young or too old to evacuate; the population had fallen from 420,000 in 1942 to 245,000 in 1945, leaving mostly children, caregivers, adults in war work, government employees and 40,000 soldiers. The book makes no pretense at being ‘objective’ on the subject of nuclear weapons, describing bodies carbonized and blown apart by their impact. “If you are going to defend these weapons’ use, it is morally imperative that you own that image,” Sheftall says, after dismissing antiseptic alternatives such as ‘vaporized.’

“Turn it around in your head a bit. Imagine it happening to ten thousand children or even a single child. Imagine it happening to your child.”

The following contains edited extracts from an interview with David McNeill.