I managed to wait on this one, despite all the hype that built up around it and all the spoiler dodging I had to do. Of course, being about to go into several months of overtime helped too.
Overall, though, this book was an enjoyable experience, much better than Harry Potter and the Order of the Phoenix as most of the problems I had with that book have been resolved. Harry is no longer screaming with adolescent tantrums, we finally have a three dimensional Slytherin who isn't a scheming evil-doer (or suspected of being one), the author's tendency to bring up old plot points out of nowhere without explaining them has vanished, the number of new characters has been drastically reduced, and it seems that less people have been hit on the head with a stupid stick.
There were, however, still some issues I had with the story, some obviously being things Rowling will likely wrap up in the future and others that will probably not.
I suppose the best place to start is the Half-Blood Prince character of the title, whose identity is a mystery for much of the book. Initially it seemed to me as though Voldemort may have been the Half-Blood Prince of the title, because he is a power monger and had been since his Hogwarts days, and he is known to be a half-blood, with one wizard parent and one non-practicing "Muggle" parent. Also, this book began delving into Voldemort's past, to give Harry ammunition into the methods of his enemy. But having Voldemort be the Half-Blood Prince would have been too obvious. And there was the matter that Voldemort apparently hated the fact he was a half-blood so using it in a nickname of any kind would have been most unlike him.
The Half-Blood Prince as a character is frequently present, even if he's not actually there because he resides as a personality in Harry's Advanced Potion-Making textbook. The Prince apparently was a brilliant student who had written numerous notes in his old textbook, improving on the formulas therein and well as adding spells of his own creation, and then for some reason or other left his textbook behind and it was subsequently given to Harry, who hadn't scored well enough on his O.W.L.s at the end of last year to qualify for advanced potions under Professor Snape's tutelage, but decently enough for the new potions professor Slughorn and thus found himself in sudden need of a new textbook. Thanks to the Prince, Harry excels in his potions class when he would otherwise be just barely muddling through. The Prince's formulas even beat the pants off anything Hermione creates, and she's normally the best in the Sixth Year class.
Given that the Prince knows better than his professor and the textbook writer, and his ability to make up spells, it became a natural guessing game to try to figure out who was the Prince. I'm not sure why I was so certain it had to be a pre-existing character, but perhaps I figured it's so late in the actual series to introduce an adult character of note, and it would have to be an adult character given that time that had passed since the Half-Blood Prince was in school (and Harry only has one more year of school to go so there's hardly a barrier left between him and adulthood). For a while I had suspected good old Headmaster Dumbledore might have been a prankster in his youth.
But when Harry discovers the Sectumsempra spell, marked as being used for enemies, and uses it on Malfoy, it becomes apparent that there's no way that the Half-Blood Prince could ever have been Dumbledore. A teenage wizard who comes up with a way to cut up the face and chest of his opponents could hardly have become a person like the Hogwarts Headmaster.
So that left a different possibility, one that I began to suspect, but had trouble believing. Of course, that turned out to be the right one, and because of that it tangles itself up in just about everything else I've been wondering about since I finished reading this installment.
Severus Snape, the double-agent wizard playing Hogwarts on the one side and Voldemort on the other was the Half-Blood Prince in his youth, as revealed far too late in the book to really make any difference. It really felt that it was just thrown in there and I didn't see why it made such a difference that Snape and the Half-Blood Prince were the same person (other than it makes Snape much more creative than I'd initially thought). Also, being that he was being given title billing alongside Harry Potter it seems that Snape's double role in the story should have tied together in some fashion other than having Harry simply discover his hated instructor was also his study buddy. If it had caused Harry to feel some kinship with him, something that would not be shaken even by Snape's apparent betrayal, then it might have been worthwhile, but it didn't. I guess what I'm saying is... it didn't change the story. Harry Potter and the Half-Blood Prince could have been the same story it is now without ever even using the Half-Blood Prince.
Also, since the only way Harry found out that Snape was the Half-Blood Prince was when Snape told him (right when he was making his get-away near the end of the book), that left little to no time to explain where that title had come from or for the reader to accept the answer given, especially since that only answer is mere speculation on Harry's part and we know he's a biased party. Snape is apparently the son of Eileen Prince, a pure-breed wizard who married a Muggle... so he is literally a half-blood Prince. Harry feels that Snape picked the name in the same fashion that Tom Riddle renamed himself Lord Voldemort, to give himself an impressive new name because he was ashamed of his parentage and wanted to make a name for himself in the Dark Arts.
I have bit of a problem with that though because of the half-blood part. Voldemort might be half as well, but hates it. Snape dislikes mudbloods as well, but if he chose Half-Blood, even if it just referred to him being related to a pureblood family, he surely must have known it could be read the wrong way, especially if he ever publically used the nickname. Also, unlike young Voldemort, Snape was apparently unpopular, even lonely, in school, so it would seem that his title would be more a wish-fulfillment than something he ever used. Perhaps secretly he was pleased with being both pure and Muggle or he liked being thought of as tainted? There are no notes on his upbringing, but if his purebred mother didn't care about marrying a Muggle (and assuming the marriage hadn't ended badly) it would seem odd that Snape would have that kind of bias. Since Snape had called Harry's mother a "mudblood" in the previous book I had taken that to mean he was a pureblood, which Slytherins are noted for preferring. While it's possible that Snape also had a bad childhood and blamed it on his Muggle father, that sounds strikingly like Voldemort's story, which if duplicated, weakens the character behind them both.
My difficulty with the title the Half-Blood Prince is something I doubt will be resolved in the seventh and last book, and the explanation here felt too flimsy, too weak, but hopefully the rest of what kept my mind stirring will be handled in the future. It is also, unsurprisingly, related to Snape and a hope that Rowling can pull a rabbit out of a hat with this one because there's only one book left to reveal what this guy's motivations are once and for all.
In this book we find out that Voldemort has not only accepted Snape back into his services, but that he apparently is his favorite servant (according to the words of the other Death Eaters). Considering everything that Snape didn't do in service of the Dark Lord in comparision to the rest of the Death Eaters in previous books, this is something of a surprise, and Rowling does a large info dump that answers every point of skepticism that a person might have, straight from Snape's own mouth. Problem is, given that he's talking to a distrustful Death Eater, can he be believed? He points out that the Dark Lord has asked every one of those questions of him (and if we are to believe Voldemort isn't an idiot, that seems a reasonable assumption) and since Voldemort is an accomplished Legilimens (something like a truth-reader/interrogator), he would have found out if Snape was lying. Thus, the fact that Snape has regained his status as Death Eater despite missing the summons at the end of the fourth book is presumably because Voldemort believes that Snape had taken actions in his best interests and forgave the transgression.
If Snape is really well and truly trusted by Voldemort and he told Voldemort the truth, then that creates issues with the fact that Dumbledore trusts him implicitly. Given Snape's background as an ex-Death Eater it would seem that Dumbledore would have needed an extremely very good reason to trust him at all, let alone completely, which he has stated numerous times whenever anyone had reason to doubt Snape (which was quite frequently). The upshot is that Snape would have to have fooled one or the other of the most powerful wizards on Earth into believing he was still their loyal and trusted ally.
Despite the fact that Snape killed Dumbledore at the end of the book (the death I expected when I heard someone died in this book, but certainly not the murderer I expected!), I think it remains to be seen which side Snape is truly on. The story is set up so that the characters believe that Snape has really been an agent of the Dark Lord the whole time, but his killing of Dumbledore could instead be a case of following orders to the extreme. Also, from a plot perspective, it seems really stupid to have a villain who everybody except for one person would have had reason to doubt the entire series only to one day reveal that "woah, he really is a bad guy."
In Snape's favor of being a good guy, there is Dumbledore's unshakeable faith in him, the fact he saved Harry's life as a way of paying a debt to Harry's father for saving his own (and this before he was aware Voldemort would make a comeback), and then his behavior in chapter 2 of this book where one of the Death Eaters questions his alligeance and the other has come for his help. In that chapter he looks away when Narcissa cries her son Draco will be sacrificed by the Dark Lord on an impossible mission (which turns out to be to kill Dumbledore) "as though her tears were indecent, but he could not pretend not to hear her." To me sounds like he has a heart and feels her pain, no matter that they are both Death Eaters. And then there's the kicker when Snape makes an Unbreakable Vow to protect Draco and then should Draco fail, to perform the test himself that Draco could not do. Right at the beginning of the story it becomes apparent that Snape will have to do something horrible (since it's presumed from the get-go that the task is too big for Draco), and it's difficult to tell if he made the vow because he had no choice, his cover would otherwise be blown, because he truly feels compassion for Narcissa's predicament, or both. Snape did twitch when he was asked to agree to the final part of the vow, to perform Draco's task should he fail, so obviously the idea did not sit well with him even though he swore to it.
At the end of the book we see that Draco does have the opportunity to kill Dumbledore, but is unable to follow through, which I found incredibly redeeming for his character, who has been entirely one-dimensional in the past. Draco finally realizes that all the bragging in the world doesn't mean anything if it cannot substantiated, and he also realizes that he isn't quite the malicious badass he made himself out to be. He has ample opportunity to do in his target and win Voldemort's approval, but instead when he can't do it, Snape steps in and with a look of pure hatred and revulsion on his face, slays Dumbledore. Was that hatred because he hated Dumbledore and thought him a fool? Or was that because he hated what he had to do, that his loyalty to the one man who ever forgave him of his crimes forced him to slay that very same person in order to retain his cover as a Death Eater as a part of Dumbledore's plans? When Dumbledore looked at Snape, pleading, was he pleading for help or for Snape to carry through and kill him?
We will have to see in the final book, and if I still can't figure out what's going on with this guy at the end of the seventh book I shall be very upset. It was quite a blow to my admiration of his character to see all the raging hatred on his face when he killed Dumbledore and when Harry accused him of being a coward. At first I wondered why Snape was so upset that Harry called him a coward, if there was something in his past that he gone through before, but now that I think about it, if Snape is still a good guy, it may have been because of the guts it took to follow Dumbledore's plan, no matter the cost. A coward would have backed out, ruining months, years, of work and endangering countless lives. Carrying through with such a gruesome task, if Snape is still one of the good guys, is truly the mark of a soldier. By this time in the book, Dumbledore has passed on everything to Harry that he could possibly teach. If sacrificing his own life was necessary for others to carry on, Dumbledore would do it and expect Snape to carry through.
Regarding the other key portions of the book, Voldemort's past is finally revealed and while there's certainly some sympathy for the plight of Voldemort's mother, there's not really any for Voldemort himself. He was a self-made jerk and never really deviated from that except that the stakes became exceedingly greater, to the point he became obsessed with immortality and was willing to kill people and maim his soul to create what are known as Horcruxes (objects that store a portion of a wizard's soul so that when his body dies he's not truly dead). Voldemort is apparently so evil that while splitting one's soul in two is already considered heinous, the Dark Lord has done it no less than six times. Since he's apparently an eccentric as well, he's split his soul into the magic number seven (or so Dumbledore presumes), creating six Horcruxes and leaving the seventh piece in his body.
While two of the Horcruxes are known to have been destroyed by the end of this book, that still leaves four for the next, which is an uncomfortably large amount, especially since the previous two were not integrated with the story as being the objects of a quest at the time they appeared.
Harry and Dumbledore did try to get a third Horcrux, and braved a very gruesome set of guardians to get it (I'm not relishing the thought of seeing movie versions of those!), but in what I find an admirable as well as annoying twist, Harry discovered after Dumbledore's murder that the third Horcrux they discovered is actually a fake. While it was a great emotional punch to think that Dumbledore had died for nothing (since it was getting the fake Horcrux that had weakened him so much that Malfoy was able to corner him), it also introduced a brand new character, the mysterious R.A.B., who had also discovered Voldemort's secret and escaped with the Horcrux, leaving a fake with a note in its place.
Who R.A.B. is, is not discovered (being so close to the end of the book), but this person obviously knows as much about Voldemort's past and inclinations as Dumbledore does. Worse, R.A.B.'s note says that he/she will be dead by the time that Voldemort discovers the fake, but wanted to be sure that Voldemort knew who had done it, suggesting something of a personal relationship as well as making the reader realize that we will probably not see this person alive in the next book. So it was essentially a minor character who had done something significant in the past who was being introduced in the third to last chapter of the book.
I don't know where Rowling is going with the seventh book since so much as been uprooted in Harry Potter and the Half-Blood Prince. That Dumbledore should die was not unexpected. If Harry is to truly have his darkest hour, then he has to lose his mentor and greatest ally. But now some of the other tropes that have been in every book since the beginning may be gone for good. The ending leaves the children uncertain if Hogwarts will even reopen given all the problems Voldemort has caused, and even if Hogwarts does reopen, Harry has made it clear that he will not go back because he must face the Dark Lord and put an end to him.
Hogwarts has been the framework within the readers played for every single installment of the series. It's as much a character as Harry, Ron, and Hermione. Without Hogwarts, virtually all the student supporting cast will be gone (Ginny will probably come back, being Ron's sister, but what about Luna?) as well as the majority of the professors and quite a few of the more minor locations and characters. There will be no more shopping runs to Diagon Alley for school materials, visiting Platform 8 and 3/4s on getting on the train, or day trips to Hogsmeade.
Can the seventh book stand on its own without the familiar setting of Hogwarts and so much of the character that had come with it? I suppose we'll see.