JK Rowling answered some questions from children during a press conference for Harry Potter and the Half-Blood Prince this past weekend. The questions covered all the books, where her ideas came from and even some questions in reference to book 7.
Some questions the children asked:
JK Rowling:The thing that Voldemort fears more than anything else is his own death. It its the quest of his life to cheat death, so we would have to see himself lying dead on the floor.
David Moulds for the News of the World - How does Aunt Petunia know about dementors and all the other magical facts she knows?
JK Rowling: Another very good question. She overheard a conversation, that is all I am going to say. She overheard conversation. The answer is in the beginning of Phoenix, she said she overheard Lily being told about them basically.Is that true?
JK Rowling: Yes. The reason I am hesitant is because there is more to it than that. As I think you suspect. Correctly, but I don't want to say what else there is because it relates to book 7.
Samatha Scattergood for Waterstones - Which is your favourite member of the Order of the Phoenix?
JK Rowling: I keep killing all my favourite members of the Order of the Phoenix, but there is one member of the Order of the Phoenix that you have not yet met properly and you will well, you know that they are a member, but you haven't really met them properly yet and you will meet them in seven, so I am looking forward to that.