Taking part in a global town hall, she announced her plans in response to a question about her future plans.
“I don’t know what I will say in it yet,” she said. She said that first she has to catch up on "about 20 years worth of sleep deprivation."
On CNN last Sunday, presidential historian Douglas Brinkley said she would likely write such a book, when talking about what Clinton would do after leaving office as Secretary of State. "She needs to work on a memoir, she'll probably give speeches. At that point, in about 18 months or two years, [the Clintons] have a big decision to make," he said.
Clinton has already written a bestselling memoir, Living History, published in 2003, about her suburban middle-class upbringing and her time as First Lady in the White House. She also wrote It Takes A Village, a book about child development, published in 1996.
Of course, though Clinton continues to refuse to be drawn on the question, publishing a book can sometimes be a sign of intent to stand as a presidential candidate. As The New York Times wrote in 2007,
For candidates, writing a book is a way to make money, build gravitas and grab media attention. (They can also use a memoir as a dumping ground for past unpleasantries, paving the way for the campaign-trail line “I addressed that in my book.”)
Last year, Monica Lewinsky made headlines when it was reported that she was writing a memoir, but thus far, no further news about that particular book has emerged.