What Happened, due out in September, will tell her story of the electoral battle with Donald Trump in ‘a deeply intimate account and a cautionary tale for the nation’

Hillary Clinton has promised that she will be “letting [her] guard down” in the most personal book she has yet written: a memoir due out in September that will reveal her thoughts on last year’s US presidential election.

“In the past, for reasons I try to explain, I’ve often felt I had to be careful in public, like I was up on a wire without a net. Now I’m letting my guard down,” writes Clinton in the introduction to What Happened, which was announced by publisher Simon & Schuster on Thursday.

Clinton told US press: “It will also give readers an idea of what it’s really like to run for president, especially if you’re a woman … Ultimately it’s about resilience, how to get back up after a loss.”

Simon & Schuster said the book would cover what it was like to run against Donald Trump, the mistakes Clinton feels she made, and how she coped with losing her bid to be the first female American president in November 2016.

“She speaks about the challenges of being a strong woman in the public eye, the criticism over her voice, age and appearance, and the double standard confronting women in politics,” said the publisher. It had previously announced a book of Clinton’s essays for September, but said the book had now evolved into a “full memoir”.

“She lays out how the 2016 election was marked by an unprecedented assault on our democracy by a foreign adversary. By analysing the evidence and connecting the dots, Hillary shows just how dangerous the forces were that shaped the outcome, and why Americans need to understand them to protect our values and our democracy in the future,” said Simon & Schuster. “The election of 2016 was unprecedented and historic. What Happened is the story of that campaign and its aftermath – both a deeply intimate account and a cautionary tale for the nation.”

Clinton is not the only member of her family with a book due to hit the shelves: her husband, Bill, is currently working on a thriller with the bestselling novelist James Patterson. The President Is Missing is out next summer and will, said publisher Penguin Random House, “offer readers a unique amalgam of intrigue, suspense and behind-the-scenes global drama from the highest corridors of power. It will be informed by details that only a president can know.”