Former first lady Michelle Obama signs copies of her memoir "Becoming" at the Seminary Co-op Bookstore in Chicago, Illinois, U.S., November 13, 2018.

Former first lady Michelle Obama's memoir "Becoming" has become the fastest-selling book of 2018 at Barnes & Noble, surpassing the Trump administration tell-all "Fear: Trump in the White House" by veteran journalist Bob Woodward.

In addition to being this year's fastest seller, Barnes & Noble also announced that "Becoming" had the best first-week sales of any adult book since 2015's "Go Set a Watchman," the highly anticipated second novel from "To Kill A Mockingbird" author Harper Lee.

Publisher Penguin Random House announced that "Becoming" sold more than 725,000 copies on its first day of release last week, the highest single-day sales of any book by the publisher this year.

"Becoming" chronicles Obama's path from a child growing up in the South Side of Chicago to her time as first lady of the United States. The book also features Obama's harshest public criticism of President Donald Trump. She writes that she will "never forgive" Trump for spreading the baseless "birther" conspiracy theory that Barack Obama was not born in the United States.

"What if someone with an unstable mind loaded a gun and drove to Washington? What if that person went looking for our girls? Donald Trump, with his loud and reckless innuendos, was putting my family's safety at risk. And for this I'd never forgive him," Michelle Obama writes.

Obama's memoir is just the latest in a series of splashy political book releases this year. Barnes & Noble said in October, just before the midterm elections, that there had been a 57 percent boost in political book sales from a year earlier.

Woodward's "Fear" sold 900,000 copies on its first day and 1.1 million in the first week, breaking records at the 94-year Simon & Schuster.

Former FBI Director James Comey's "A Higher Loyalty" sold 600,000 copies in its first week in April, while the controversial "Fire and Fury: Inside the Trump White House" by Michael Wolff sold 192,000 books during its first week in January.

Hillary Clinton's election post-mortem, "What Happened," had the lowest sales of the bunch, notching 167,000 copies sold during its first week last September.

Michelle Obama is currently promoting "Becoming" on a cross-country book tour that has filled arenas with crowds in the thousands.

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