Our resident Potter expert, Lizo, has naturally read the Half-Blood Prince already and has told us his initial thoughts on the plot and what the horcruxes could mean for the future of Harry Potter.
Here's what he had to say:
First impressions are that I really like this book, more than most of the others - the exception being Prisoner of Azkaban which remains the standout of the series.
The thing I like about it is that it's answering so many things thrown up by the first few books. And it's shown how brilliantly JK Rowling has planned the whole series. If my theories are correct, she's been incredible at intricately constructing her seven-book plot.
And I've also got a few theories which I'll explain more of later. Of course, a lot of these are to do with horcruxes.
I believe the seven horcruxes are...
1. Voldemort himself
2. Harry Potter!
3. Tom Riddle's diary - destroyed
4. The ring - destroyed
5. The locket - now located at Grimmauld Place
6. The cup - location unknown
7. An object once owned by Ravenclaw
I'm not convinced that the snake Nagini is indeed a horcrux, there's every possibility that Dumbledore was wrong. So working on the assumption that it isn't, what are the others?
Well, one has to be Lord Voldemort. We know that two were the ring and the diary. Leaving four. It would give the final book a wonderful elegance if the final four horcuxes were each related to the four founders of Hogwarts.
One being Hufflepuff's cup, another being Slytherin's locket, one more being an object related to Ravenclaw and the last being something related to Gryffindor.
The cup's whereabouts are unknown, and the object that may be related to Ravenclaw's location is unknown too.
As for the locket, well we know it was taken by someone with the initials RAB. A plausible identity for this person would be Regulus Alphard Black.
We know that Sirius's younger brother killed on Voldemort's orders was called Regulus Black. He and Sirius had an uncle called Alphard, so he conceivably could have been named after him too.
In chapter six of The Order of the Phoenix, Harry is helping clear out Grimmauld Place. Among the things they find is a heavy locket that none of them could open. Although it's not described as having a Slytherin S on it, there's a good chance that this could be the locket/horcrux.
And the final horcrux. Why Harry? Well, the other remaining three are related to Slytherin, Ravenclaw and Hufflepuff. A long-established theory is that Harry is the last remaining descendant of Godric Gryffindor, hence his parents' residence in Godric's Hollow.
But how could Harry become a horcrux? Well, when Voldemort set out to kill Harry Dumbledore believes he was one Horcrux short. What if, when Voldemort's curse rebounded from Harry onto himself this act of 'murdering himself' created the means for another horcrux to be created, and accidentally perhaps a piece of Voldemort's soul was transferred to Harry when the curse failed, along with various other powers such as parseltongue, of course.
Hence, Harry's scar is a symbol of him being a Horcrux. Can we find collateral evidence for this? Let's have another look at the prophecy.
'The Dark Lord will mark him as his equal'. If my theory stands up, then Harry truly is marked by his scar as Voldemort's equal, because both Harry and Voldemort contain one seventh, an equal measure, of The Dark Lord's soul!
And 'either must die at the hand of the other for neither can live while the other survives' - that could be referring to the fact that because Harry contains Voldemort's soul, as he grows older they can't both occupy the same body. So eventually Voldemort's soul will completely take over, and kill, Harry. Or Harry will force Voldemort's soul out of his body, and kill him like that.
How does this make Harry special, as the only person who can kill Voldemort? A crucial question is, why did destroying the ring horcrux almost kill an immensely powerful wizard like Dumbledore? Whereas when Harry destroyed the diary, it didn't harm him at all. It seems that both objects would have been equally well protected by Voldemort against destruction. So the conclusion we must draw is that Harry has powers that Dumbledore doesn't.
Maybe when he finds other horcruxes he absorbs those parts of Voldemort's soul into himself too. And perhaps this has already happened when Harry destroyed the diary. He may have absorbed another seventh of Voldemort's soul making him more and more powerful.
Have we seen evidence of this yet? In Goblet of Fire, when Harry manages to force the beads of light back towards Voldemort, maybe this is a symptom that Harry is more powerful as he has more of Riddle's soul.
And this would certainly, once again, underline the prophecy, in that Harry's been given the power to destroy Voldemort, because he's been given a head start in being able to gain power through taking in the remaining three.
So when Harry finally faces Voldemort, he may well contain four sevenths of Voldemort's soul!
Well, that's my hunch anyway. Could be right, partly right or completely wrong. Only one person knows, and she's not telling!
Other things about the book - is Snape evil or not? As Ron said in the chess game in Book I, you have to make sacrifices. If Dumbledore knew that Voldemort would finally get him, but that he could die in a way that would enable a member of the Order to be one of Voldemort's closest advisers, I'm sure that Dumbledore would consider this a sacrifice worth making.
When Dumbledore, one of the greatest wizards ever, is about to die he pleads with Severus. Dumbledore is not the kind of person who would plead for his life! He'd just say I'm sorry I was wrong Severus, do what you must.
But he is the kind of wizard who would plead with a friend to do something that they hated doing with all their soul. I'm certain that Dumbledore wanted Snape to kill him, to help protect Harry in the future, and he knew that Snape didn't want to do it. Not doing it would also, of course, have killed Severus, after he made the Unbreakable Vow. Probably on Dumbledore's orders.
Will Harry return to Hogwarts? I'm sure he will, and it would make sense for a least one of the horcruxes to be hidden there. Putting aside the Harry horcrux theory, maybe Tom Riddle's Award for Special Services to the School? Also Dumbledore appeared to forget about another Gryffindor relic - The Sorting Hat!
Well, we'll find out all these things in Book VII, which JK Rowling has said is at least two year away.
There are a couple of auspicious dates if it can be written within two years - the 7th of July, which would see the 7th book released on the 7th day of the 7th month of the 7th year of the Millennium. 7/7/07. It's a Saturday night rather than a Friday! But maybe they could release it at 7pm!
Or what about the 26th June 2007 - that would mean it being published on the 10th anniversary of Philosopher's Stone hitting the bookshelves.
Whenever the book is released, we've still got a while to wait. And in the meantime we'll all be coming up with more and more theories.
I'll have some more soon!