In the passage from Clinton’s memoir, “What Happened,” the former secretary of state recounts an "incredibly uncomfortable" moment during the second presidential debate in St. Louis on October 9, in which her "skin crawled" as Trump was "looming behind" her and "literally breathing down [her] neck." A day prior, the Washington Post had released a video from 2005 of Trump making lewd comments about sexually assaulting women.
"Well, what would you do? Do you stay calm, keep smiling and carry on, as if he weren't repeatedly invading your space?" asks Clinton in the book. "Or do you turn, look him in the eye, and say loudly and clearly: 'Back up you creep, get away from me. I know you love to intimidate women, but you can't intimidate me, so back up.'"
Clinton explains that she chose to maintain her focus on the debate, "aided by a lifetime of dealing with difficult men trying to throw me off," but admits she contemplated whether she should have taken the more direct approach.
"It certainly would have been better TV," she says in the clip from the audio book, which she reads.
"What Happened," which is being published by Simon and Schuster, is scheduled for release on September 12. The memoir of Clinton's experience as the first female presidential nominee of a major party will be her third book.
"I don’t have all the answers, and this isn’t a comprehensive account of the 2016 race," says Clinton in a portion of the author's note also obtained by ABC News. "This is my story. I want to pull back the curtain on an experience that was exhilarating, joyful, humbling, infuriating and just plain baffling."
"Writing this wasn’t easy," she adds. "Every day that I was a candidate for president, I knew that millions of people were counting on me, and I couldn’t bear the idea of letting them down -- but I did. I couldn’t get the job done, and I’ll have to live with that for the rest of my life."
ABC News' MaryAlice Parks contributed to this report.