Harry Potter and the Half Blood Prince
After the rumors of the other name of her book six went abound, J.K. Rowling has decided to set the record straight with the truth. She had this to say about it on her website:
Title of Book Six: The Truth
Well, the door opened at last and I showed you the title of book six - the genuine title, the title that will appear on the published book, the title I have been using in my head for ages and ages. Unfortunately, however, the door opened on the very same day the 'Pillar of Storgé' hoaxer struck, which left a lot of Harry Potter fans bemused as to whether I was having a joke at their expense by posting another fake title to 'teach hoaxers a lesson', something I certainly wouldn't do, as it would simply frustrate, confuse or annoy the 99.9% of you who aren't hoaxers! I tried to give a clear hint that the title behind the door was the real one by making the 'Toenail' joke as well (see 'Rumours'). But just to clear up matters once and for all…

Information you take directly from this site will be truthful and accurate (I might occasionally joke, but as time goes on, you'll learn to tell when I'm joking). Do not trust anybody else claiming to have found information on this site that you cannot access, however seemingly convincing the images they provide to support their story.

I never post information on the site that I do not want fans to read immediately. In other words, anybody claiming to have 'discovered' a message that wasn't due for release yet is lying. There was never anything meaningful behind the door until the 'Do Not Disturb' sign came off!

The 'Pillar of Storgé' was never my title, and I did not change it at the eleventh hour because I was 'found out' (I nearly fell off my chair giggling when I read this).

I was delighted to see that a hard core of super-bright fans knew that the real title was once, in the long distant past, a possibility for 'Chamber of Secrets', and from that deduced that it was genuine. Certain crucial pieces of information in book six were originally planned for 'Chamber of Secrets', but very early on (first draft of Chamber) I realised that this information's proper home was book six. I have said before now that 'Chamber' holds some very important clues to the ultimate end of the series. Not as many as six, obviously, but there is a link.

Anyway: if you continue to exercise patience, you will find that the Do Not Disturb Door opens again… and again… giving you further hints about book six. But as a little bonus, and compensation for having been messed around by Mr. or Ms. Storgé, I shall tell you one thing without making you shift any bricks at all: the HBP is neither Harry nor Voldemort. And that's all I'm saying on THAT subject until the book's published.
To go to J.K. Rowlings' Official Site.