“Becoming,” the new memoir by former first lady Michelle Obama, is the fastest-selling book of the year, according to Barnes & Noble.

The retailer announced that first-week sales of “Becoming” even outstripped first-week sales of Bob Woodward’s “Fear.” Obama’s memoir, which officially went on sale Nov. 13, had the best debut of any adult book since Harper Lee’s “Go Set a Watchman” in 2015.

“We knew ‘Becoming’ was going to be one of the biggest books of the year, but it has now officially had the best first week of sales of any book in 2018, and is among the fastest sellers in Barnes & Noble history,” said Liz Harwell, senior director of merchandising at Barnes & Noble. “This is definitely the must-have book of the holiday season.”

The record-breaking first-week sales of “Becoming” at B&N may not be reflected across all booksellers. Woodward’s “Fear” sold more than 1,100,000 copies through its first week in all formats at all retailers.

“Becoming” sold more than 725,000 copies on its first day, according to Penguin Random House.

The instant success of the former first lady’s memoir did not catch anyone off guard. Presales of “Becoming” were higher than any other book in the past three years. “Becoming” was also the No. 1 most-sold book on Amazon.com for the week ending Nov. 11 – two days before the book was available. (Amazon’s chief executive, Jeffrey P. Bezos, owns The Washington Post.)

Oprah Winfrey chose “Becoming” for her book club and helped launch the memoir at a sold-out appearance with Obama in Chicago last week. It was the first stop on a 10-city book tour across the country.

On Saturday, Obama was in Washington, D.C., at a sold-out event in the Capital One Arena hosted by Valerie Jarrett, a former senior adviser to President Barack Obama. The former president made a surprise appearance, too.

The next stop on the “Becoming” book tour is Boston on Saturday, at an event hosted by Michele Norris, former host of NPR’s “All Things Considered.” The cheapest tickets still available are $495.50. The most expensive seats are $1,000.

Book buyers in Washington have been enthusiastic, but the city’s biggest independent bookstore isn’t seeing a new record yet. Politics and Prose co-owner Bradley Graham said, “Sales of ‘Becoming’ have been very strong, although not as strong for us in the first few days as ‘Fear’ was. We have high hopes that Michelle Obama’s book will continue to sell very well through the holiday season.”

This has been a year dominated by political books – especially books about President Trump. After “Becoming” and “Fear,” the third-best debut week was enjoyed by “A Higher Loyalty,” a memoir by former FBI director James B. Comey.

Penguin Random House reportedly paid Michelle and Barack Obama $65 million for a two-book deal.