This interview re-airs on Friday, Aug. 31.

In this installment of Greater Boston's special half-hour interview series, Emily Rooney sits down with the best-selling author of "When Bad Things Happen to Good People."

As a young rabbi, Harold Kushner often grappled with how to console grieving members of his congregation. Then his firstborn son, Aaron, was diagnosed with progeria, a disease that prematurely ages a child. With a limited lifespan, each milestone Kushner and his wife Suzette celebrated with Aaron also meant a milestone closer to the boy's inevitable and untimely death. 
After Aaron died in 1977, just after turning 14, Kushner used his own grief to answer some fundamental questions. Why do some people who have lived according to all the principles of goodness, still have to suffer through pain? His first book, "When Bad Things Happen to Good People," tackled those questions and touched a nerve, becoming a bestseller. 
Kushner's personal tragedy transformed how he dealt with congregants. "I'm embarrassed now to remember some of the things I said in those first few years. That changed right after Aaron was diagnosed with the disease," he said.
At first, he tried to tell himself what he had said to congregants — parents whose sons died in their teens, people whose loved ones had been killed in accidents. He would tell the bereaved that their loss was part of God's plans — plans that were not for them to understand.
His own tragedy thrust him into a crisis questioning how he could continue to be a rabbi, and whether or not he believed in a God who would inflict this kind of pain on good people.
"God is on our side, not on the side of the illness" or the tragedy, he now tells his readers. "Homeowners insurance doesn't prevent your house from catching fire. It ensures that if that should happen, you'll have the resources to rebuild it. Life insurance policies don't keep you from dying. They make sure that should something happen to you, your family will be able to go on."
And so, he said, a belief in God and religious faith should act the same way; giving people the resilience they need to protect against breaking when misfortune strikes.
He also has come to believe it's important to overcome the belief that God makes everything happen for a reason. Kushner often referred to the 23rd Psalm during funerals and memorial services. To him, the psalm represented God's presence at his side during difficult times: "Though I walk through the valley of the shadow of death, I will fear no evil, for Thou art with me."
Kushner said when he originally started claiming God doesn't control everything, he was treated like a heretic. But now, he said, it's become an acceptable notion. "We have confused God with Santa Claus," Kushner said. "We think the role of religion is to persuade God that we have been good girls and boys, and therefore He ought to give us everything on our wish list. That is Santa Claus. That's not God. God's role is to give us a sense of what is right, and to give us the strength and purpose to do it, and to sustain us when things don't work out for us."
But to Kushner one of the best lessons on how to live life comes through the book of Ecclesiastes: "Life is unpredictable. Find joy where you can," is what Kushner took from the book. "Enjoy life with a person you love. Let your clothes always be freshly laundered. Eat your food in gladness, and drink wine in joy. Because that's really the payoff for being alive."
Now 35 years have passed since Aaron's life and death transformed Kushner's outlook on life. Kushner was grateful to have emerged with his faith intact. Still — "Would I have rather had a normal child, and ended up being a mediocre rabbi who never had a book published in his life?" he asked.
"Yes," he concluded, "I would go for that in a moment."