Conversation so far:
Who was the half blood prince?
Voldemort was the half-blood prince.
What is JK Rowling's book Harry Potter and the Half-Blood Prince about?
Set during Harry Potter's sixth year at Hogwarts, the novel explores the past of Harry's nemesis, Lord Voldemort, and Harry's preparations for the final battle against Voldemort
When was JK Rowling's book Harry Potter and the Half-Blood Prince published?
The book was published in the United Kingdom by Bloomsbury and in the United States by Scholastic on 16 July 2005

Question: Was the book a bestseller?
Self-contained rewrite: Was JK Rowling's book Harry Potter and the Half-Blood Prince a bestseller?