Former President Barack Obama's new memoir is on track to be the best-selling presidential memoir in modern history. "A Promised Land" sold nearly 890,000 copies in the U.S. and Canada in its first 24 hours. The only book by a former White House resident to come close to this pace? Someone the president knows very well -- his wife and former First Lady Michelle Obama. Her memoir "Becoming" sold 725,000 copies in North America on its first day and has topped 10 million worldwide since its release in 2018.