Michelle Obama’s star power continues to prove itself with the success of “Becoming,” part memoir and part self-help book. Crown Publishing announced that more than 3 million units have been sold so far.

“Becoming” is one of the fastest-selling nonfiction titles ever and promises to become one of the best-selling political memoirs of all time. Within a few weeks of its release on Nov. 13, it became the best-selling book of 2018, with more than 2 million copies sold in all formats. It has been published in 33 languages and is currently in its sixth printing, with about 6 million copies in print worldwide.

Live Nation, which typically promotes concerts at large venues, is managing Obama’s book tour, called “Becoming: An Intimate Conversation with Michelle Obama.” Capitalizing on surging interest in her story, the former first lady added 21 more appearances in 2019. The new dates nearly triple the size of the original 12 planned for 2018.

Of the new stops, 11 are in the United States, four in Canada and six in Europe. Obama will begin her 2019 schedule with a stop in Tacoma, Wash., on Feb. 8 and end it in Nashville on May 12. Her other U.S. stops include Portland, Ore., Phoenix, Austin, Houston, St. Paul, Milwaukee, Cleveland, Fort Lauderdale and Atlanta.

Promotional appearances for her blockbuster memoir have been heavily attended, taking on the proportions of rock concerts. Fans who bought tickets costing hundreds of dollars have packed giant arenas to hear the former first lady speak about her life growing up and her experience in the White House, where she and her husband, former President Barack Obama, spent eight years.

Obama will continue to appear in large venues, such is the demand for her time. Her book tour began in Chicago, at the United Center, home arena of the Chicago Bulls, where she was interviewed by Oprah Winfrey in November.

Last week Obama appeared in London and was interviewed at Royal Festival Hall by Nigerian novelist Chimamanda Ngozi Adichie. Obama will appear in another NBA arena Thursday, the Pepsi Center in Denver, where she will be interviewed by the actress Reese Witherspoon.

Her appearances have all followed a similar format, with a notable interviewer guiding the discussion. During a tour stop in D.C. on Nov. 17, Barack Obama made a surprise appearance, presenting his wife with a bouquet of flowers and comparing himself to Jay-Z and Michelle to Beyoncé.

Her last appearance of 2018 will be Dec. 19 at the Barclays Center in Brooklyn, where she will be making her second appearance of the month.

Hugo Kugiya, a former national correspondent for Newsday and the Associated Press, is a Seattle-based writer and editor.