As the generation that survived the nuclear attacks on Hiroshima and Nagasaki begins to pass, the grandson of President Truman works to end the threat of nuclear weapons.Here’s how his story begins … 

In June of 2012, I was driving home from taking my son, Gates, to high school when, contrary to common sense and Chicago ordinance, I decided to check the messages on my cellphone. There was only one. Someone with a lovely soprano voice was singing me “Happy Birthday.”

It turned out to be Shigeko Sasamori, who survived the 1945 atomic bombing of Hiroshima, an attack ordered by my grandfather, Harry S. Truman.

I had met Shigeko only a couple of weeks earlier, in New York. She was there working with Hibakusha Stories, a United Nations-affiliated NGO that, as of this date, has brought atomic bomb survivors to share their experiences with more than 25,000 New York Metro-area high school students.

Needless to say, I never expected to know a survivor of Hiroshima, let alone have her sing me “Happy Birthday.” My grandfather never spoke to me about the atomic bombings. I learned about them like everyone else, from history books. Aside from casualty figures, the books told me very little about what happened to the people....