New York | Prince Harry’s memoir, Spare, has become a record-breaking success, with first-day sales that exceed some of publishing’s biggest hits, including blockbusters by Barack and Michelle Obama.

Spare sold more than 1.43 million copies in all formats in the US, Canada and Britain, including pre-orders, its publisher said. The figure marked the largest first-day sales for any nonfiction book ever published by Penguin Random House, the world’s largest publisher.