Jonathan Karp, who edited Ted Kennedy's memoir "True Compass," told CBS News' Nancy Cordes that the Lion of the Senate "had been working on it for years" on "Washington Unplugged" Tuesday.
Karp said Kennedy began recounting major events in his life through conversations with a University of Virginia historian.
"Even more amazingly," Karp said, "he took personal notes begining in 1960," nearly fifty years ago.
When asked by Karp what the most important message in the book was from his persective, Kennedy said one word: perseverance.
"In fact, we even thought about calling the book perseverance but it was too hard to spell," Karp joked before detailing causes his former boss worked tirelessly for.
"He battled this illness. He knew it was terminal and I spent a fair amount of time with him and he never complained. He took it one day at a time and he was always optimistic," Kennedy's editor said. "When he got the prognosis the thing that made him the angriest was that the doctor did not seem to be telling him to fight it. It was basically just get your things in order and that was not in the Kennedy DNA"
Karp admitted that at times writing his memoir was "emotional" for Kennedy but for the most part it was fun -- he loved singing his editor said.
Watch the full interview as well as the latest on Rep. Joe Wilson (R-S.C.) above.
"Washington Unplugged" appears live on CBSNews.com each weekday at 12:30 p.m. ET. Click here to check out previous episodes.