Ted Kennedy's sons, Patrick and Teddy Jr., are well-versed in the governmental achievements of their father, but they said they were taken aback by his more personal, vulnerable side shown in the final years of his life and in his memoir, "True Compass."
"What I found so revealing was his deep emotional side and his deep spiritual side," Ted Kennedy Jr. said today on "Good Morning America."
"There were a lot of times he could feel like he could depend on us," an emotional Patrick Kennedy, 42, said as he sat alongside his older brother. "It was unlike him to actually want to lean on someone else. He was such a towering figure in our lives. ...The fact that he could express that vulnerability to us was really a big thing for all of us."
The memoir, written in the last five years of Kennedy's life, examines Kennedy's storied life and his relationship with his famous brothers.
"They were his heroes," Teddy Jr., 47, said. "In the book, it was amazing to me to realize how much he worshipped and adored not just his older brothers but all of his brothers and sisters. He did feel in many ways like he was catching up."
The book recounts Kennedy's painful struggle to tell his own father about Jack Kennedy's assassination in Dallas in 1963.
"I never understood how emotionally difficult it was to tell his father that Jack had died in Dallas," Teddy Jr. said. "I think he felt like he had to be the strong guy in our family. So many people were standing on his shoulders, he really felt like he needed to be solid."
But the essence of their father's life, the sons said, was in the name of the book's final chapter, "Perseverance."
"There isn't anyone that worked harder than my father," Teddy Jr., a lawyer and investment banker in New York City, said. "He really respected people and stuck at it and kept going."
Patrick, a Rhode Island congressman, said, "My dad was one who never took on adversity without a lot of hope and a sense of determination to overcome whatever obstacles were in his way."
One section of the book notes that while most people have coats in their closets, the Kennedy home had bullet-proof vests.
"We were always mindful when he went out in public," Teddy Jr. said. "What if there is this person that wants to become instantly famous? We weren't in denial about the reality, about how easy it would be for someone to do that."
But Ted Kennedy refused to hide, Teddy Jr. said.
"He just said, 'I can't sit here and worry about this my whole life, otherwise I'll live in a cage,'" he said.
But on the campaign trail in 1980, Teddy Jr. said, his father was stabbed in the hand by someone with the pin of a campaign button. Luckily, the tip was not poisoned, as Teddy's bodyguards feared.
"It was the first time I remember ever feeling that this was something that was a daily part of his life that he had to worry about," Teddy Jr. said.
In one of Ted Kennedy's last interviews, he half-joked about his father telling him about the public service call that dominated his family.