How many books did the last Harry Potter book sell?

The last Harry Potter book, Harry Potter and the Deathly Hallows, sold a staggering 12.3 million copies in the United States alone on its first day of release.

Globally, the book sold 11 million copies in its first 24 hours.

It's important to note that these numbers represent initial sales and don't include all subsequent sales. The book has continued to sell very well since its release.