And though some have guessed that other parts of the song are about Mick Jagger, she ruled him out in her memoir, "Boys in the Trees."
In a new interview with ABC News, she said that the real inspirations behind the first and third verses still don't know that they inspired her lyrics. So, what would have to happen for her to decide to fill them in?
"I would have to want to,” she said. “I would just have to say, 'OK, I’m gonna have to dunk you both into this fever that is people still wanting to know.' I still can’t understand that!"
Simon, now 70, released a companion album last year of all the songs discussed in the book, and wrote a score for the audiobook. Looking ahead, she said that it's possible that it will be turned into a biopic or musical.
"There are several things in the works," she said. You never know whether they’re actually gonna come into being or not, but there’s a lot that’s being talked about."
"I don’t know what exactly would make it very different from the book, but it would be obviously much more video- and much more audio-oriented," she added.
"Boys in the Trees" isn't Simon's entire life story, though. It basically ends with the end of her marriage to James Taylor, with whom she has two adult children, Ben and Sally. Her son has not read the book, she said, though her daughter has.
"I think he would feel more conflicted than Sally did," she explained. "I had told her almost everything, but when she read it all together, she was just so amazed. She said, 'I’m so proud of you for being able to tell it like it is for you.'”