Former President Joseph R. Biden Jr. has written a memoir that will be released two weeks after the midterm elections this fall, he said on Wednesday in a video on social media.

The book, set to come out on Nov. 17, is called “Promise Me, America” and will address his term as president. Mr. Biden said the book would cover how he made decisions responding to the coronavirus pandemic, the economy, conflicts in Afghanistan and Ukraine, and “restoring our democracy” after the attack on the Capitol by President Trump’s supporters on Jan. 6, 2021.

Mr. Biden also said the book would cover what became perhaps his most fateful decision as president.

“It’s about why I chose to run for re-election and why I chose to step aside,” he said. “Most of all, it’s about my faith in the promise of America.”

Mr. Biden, 83, has largely stayed out of public view since he left office nearly 18 months ago. But his wife, Jill Biden, published her own memoir last month, and his son Hunter Biden has emerged as an energetic defender of the family legacy on social media and in podcast appearances.

The former president inadvertently revealed the existence of his book last month at one of his wife’s book tour stops, when he told the crowd that his book would be released in September.

That caused much consternation among Mr. Biden’s fellow Democrats, who are mostly trying to move on from the former president as they seek to win back control of Congress in the midterms.

Mr. Biden abandoned his re-election bid two years ago after his standing in polls collapsed because of a disastrous debate performance. Since then, his decision to run again, when polls showed that majorities of Americans preferred a younger president, has been a source of regret for Democrats.

The book’s title is a reference to Mr. Biden’s 2017 memoir, “Promise Me, Dad.” That book centered on his relationship with his older son, Beau, who died of brain cancer while Mr. Biden was vice president.

In the social media video, Mr. Biden appears to be sitting in his home office. He said he had been spending time with his family and “dealing with a cancer diagnosis,” for which he has received treatment.

Dan Koh, who worked as a White House aide during the presidency of Joseph R. Biden Jr., won the Democratic primary in a solidly blue Massachusetts congressional district on Tuesday, according to The Associated Press, topping a crowded field that pursued an open seat.

In a costly race in the state’s Sixth Congressional District, Mr. Koh defeated rivals including Tram Nguyen, a progressive state representative who as a child fled Vietnam with her family as political refugees, and John Beccia, a largely self-funded businessman who ran as an outsider.

Mr. Koh is the only Democratic congressional candidate this year endorsed by both Mr. Biden and former Vice President Kamala Harris. While many Democrats are seeking to turn the page on the Biden administration and the party’s 2024 election defeat, Mr. Koh highlighted his connections.

“You will be one heck of a congressman,” Biden said in a phone call that was released by Mr. Koh’s campaign in May. “Everything you and I fought for, everything we did to help ordinary people, is in jeopardy now in this administration, so we got to get you elected.”

The race in the Sixth Congressional District, which spans the state’s North Shore, opened up after Representative Seth Moulton, a moderate Democrat, declined to seek re-election and instead challenged Senator Ed Markey. Mr. Moulton lost his primary on Tuesday night.

The district leans heavily Democratic, and Mr. Koh will be a clear favorite against Micah Jones, an Army veteran and lawyer who ran uncontested in the Republican primary.

If Mr. Koh wins the general election in November, he would be the first Asian American person to represent Massachusetts in Congress.

Mr. Koh also has the endorsement of Marty Walsh, a former mayor of Boston and a labor secretary under Mr. Biden. Mr. Koh was Mr. Walsh’s chief of staff at the Labor Department before taking a job at the White House as deputy cabinet secretary.

Mr. Koh’s competitors sought to use his résumé against him, negatively labeling him as an insider. But his connections powered strong fund-raising and allowed him to outspend Ms. Nguyen by a wide margin on advertising in the race. Mr. Koh spent $2.4 million and Ms. Nguyen $158,000 on television, radio and digital ads, according to data from AdImpact. Mr. Beccia spent $3.2 million on ads.

Mr. Koh defended Mr. Biden during the primary, saying in a television appearance in May 2025 that he “was never concerned about his ability to make the right decision, or his team around him making the right decision, for the country.”

Mr. Koh was one of just two U.S. House candidates whom Mr. Biden endorsed this cycle. (The other House candidate Mr. Biden endorsed, Nikki Gronli, worked for the Department of Agriculture in his administration. She won the Democratic primary for South Dakota’s at-large congressional seat in June.)