Harry Potter fans are finally finding out what happens to the boy wizard and his mates, as the last book in the series went on sale on Saturday.
Kids and adults queued outside bookshops around the world to get Harry Potter and the Deathly Hallows.
The book is flying off the shelves and some people think it'll become the fastest-selling book of all time.
JK Rowling's admitted there's at least two big deaths in the book, and fans are worried one of them could be Harry.
The author launched the book with a moonlight reading at the Natural History Museum in London.
It all happened at one minute past midnight on Friday, after fans had whisked themselves up into a frenzy of excitement.
Booksellers said the novel sold incredibly quickly, with one chain of shops saying they had sold 15 copies per second.
'I like it'
JK told Newsround she'd never been so excited about a launch as this is her favourite book of the series.
"Whether people like it or not, I really like it," she said.
Loads of fans camped outside shops for days to be among the first to get hold of a copy. And many shops stayed open overnight to cope with the Potter-mania.
Fans then had to decide whether to read the book from beginning to end - or turn straight to the final pages to discover whether schoolboy wizard Harry lives or dies.
Chatting to Newsround's Lizo before the moonlight reading, JK's thoughts turned to her post-Potter plans.
She said: "I'm sure you will hear from me again but at the moment I really would like to take a break for a while, and I think I probably need to because this has been so massive."
JK Rowling had a moonlight reading for 500 lucky Potter fans
It is 10 years since the first book, Harry Potter and the Philosopher's Stone, introduced Hogwarts School of Witchcraft and Wizardry.
Since then the books have sold 325 million copies worldwide, been translated into 64 languages and spawned five blockbuster films.
Click on Newsround's Player on the front page of our website to see Lizo's interview with JK Rowling at the Natural History Museum.