The new Harry Potter book has beaten sales records on both sides of the Atlantic, selling almost nine million copies in its first 24 hours.
Parties were held all over the world to celebrate the book's launch
Harry Potter and the Half-Blood Prince sold 6.9 million copies in the US and more than two million copies in the UK, beating all previous Potter records.
The sixth instalment in JK Rowling series was released worldwide in the early hours of Saturday.
The fifth Potter book sold five million copies in 24 hours in the US in 2003.
British publisher Bloomsbury said UK sales for the current book were 13% higher than first day sales of predecessor, Harry Potter and the Order of the Phoenix.
Estimates from Nielsen BookScan revealed 2,009,574 copies of Half-Blood Prince had been sold within 24 hours of release.
US sales of the sixth Harry Potter book have generated more than $100m (£57m) in revenue across the weekend - more than the combined box office sales of hit films, Charlie and the Chocolate Factory and The Wedding Crashers.
"When a book beats out movies, we're in great shape," said Scholastic's Lisa Holton.
"This is a cause for celebration, not just for Scholastic, but for book lovers everywhere," she added.