The latest and final installment of the "Harry Potter" book series sold 8.3 million copies in the United States during the first 24 hours it was on sale.
The book's U.S. publisher, Scholastic Inc., says first-day sales of Harry Potter and the Deathly Hallows, the seventh book in the series, exceeded sales of the previous installment Harry Potter and the Half-Blood Prince by more than one million books.
Bloomsbury, the book's publisher in Britain, will announce its sales figures later Monday. A spokeswoman says the company expected first-day sales of around three million books.
Legions of Harry Potter fans around the world gathered at bookstores at the moment went on sale worldwide - midnight Friday in London - so they could be among the first to get the book.
The Harry Potter anthology follows the adventures and trials of an English boy wizard as he learns to use his magical powers and confront opponents trying to kill him. Worldwide, readers have bought 325 million copies of the first six volumes in the series, which is translated into 64 languages.
Films of the first five books have earned some of the highest box-office revenue ever recorded, and movies matching the sixth and seventh volumes also are planned.
J.K. Rowling, Harry Potter's creator, had a very modest income before her first tale was published. Now 41 years old, she is now considered one of the world's richest women, with a fortune valued at over one billion dollars.
