Note: I did not read the printed version of this novel, but listened to the audiobook version, which was unabridged.  However, since it's a complete re-creation of the novel, I think this qualifies me for a review of the book and the audiobook since there's not much difference.

Having watched the previous Harry Potter movies (except "Azkaban"), I had a pretty good picture of the world and the characters depicted in them.  Although the author does a decent job of filling someone in if they have some understanding of the books' environment, if you were going to read this having never seen the movies or the previous books, chances are you'd be a bit in the dark about a lot of things. I believe this because I heard references made to the "Prisoner of Azkaban" events in the book that I didn't quite understand.

I'd heard that J.K. Rowling writes long, detailed books.  After seeing one on the shelf, you can believe that.  There's nothing at all wrong with a long book.  I've read many of them.  The important thing is that regardless of its length, the story remains engaging and interesting.  While I would certainly describe the previous books that way, I can't say that as easily about "The Half-Blood Prince".  Very often, Rowling went off on long, drawn-out descriptions of architectural features of the Hogwart's School, classrooms, offices, etc.  More than once those descriptions ran long enough that by the time the text came around to the point of the conversation, action, etc., I was a bit disoriented and disconnected from it.  While I have no problem with sharing the details of a room if it helps to set the mood for a conversation, explain how the occupant's mind works, etc., it seems like Rowling has a tendency to start the action going, "pause" it, tell you in great detail what the floor, walls, ceiling, air, sky, etc., are like, then "unpause" the action and move it a bit farther along until the scenery changes again.  To be honest, I found a great distraction from the book's story.

Since I've mentioned the "action" in the book, I guess this is as good a time as any to tell you that this was my biggest disappointment with "The Half Blood Prince".  About mid-way into the book, I was still wondering just what the heck was going to be the "big conflict" that would be resolved at the end.  It still felt like I was listening to an introductory chapter while I was half-way through the book.  When we got to around Chapter 28 or 29 (the book ends in Chapter 30), I actually still felt like I was reading an introduction to a story, rather than an actual story.

(Spoiler Alert!  If you haven't read the book and want to, skip the next paragraph and pick up at the following one.)

Not sure what I'm talking about?  It takes 30 chapters for Rowling to tell you the following:  Lord Voldemort is rounding up support and attacking muggles (normal humans) aggressively.  He's also been attacking and killing key members of the magical community.  Professor Dumbledore wants Harry to understand how Voldemort thinks, so he shares memories with Harry of Voldemort's mother in her early years, his father, the birth of Voldemort, his years in an orphanage (during which he used his magical gift to torment others), how Dumbledore recruited him to join Hogwart's as a student, how he learned that he could split his soul into pieces by committing murder and place his soul into "horcrux" (an inanimate object), and achieve virtual immortality.  We also learn that Snape is in league with Voldemort, and he has promised to protect Draco Malfoy while he is on a mission to kill someone at Hogwart's.  Harry and Dumbledore manage to track down the possible hiding place of one of Voldemort's horcruxes, and go there to retrieve it so they can destroy it.  Dumbledore is severely weakened in this effort.  When they return from this mission, they see a sign over top of the school indicating that "death eaters" have killed someone inside.  They rush there to find that it's a ruse by Draco Malfoy and some death eaters he has helped to enter Hogwart's past the school's magical protections.  Malfoy disarms Dumbledore but seems unwilling to kill him.  The death eaters want to kill Dumbledore but are under orders from Voldemort not to.  Professor Snape enters the room, pushes past Draco and the death eaters, and despite Dumbledore's pitiful pleas, kills him.  Harry is naturally distraught with the loss of his mentor, whom (due to a spell Dumbledore placed him under to protect him) he had to watch die at Snape's hand.  Snape, Malfoy, and the death eaters escape Hogwart's.  The school mourns the loss of Dumbledore.  Professor McGonegal becomes the new headmaster.  After the funeral service for Dumbledore, Harry vows that he'll destroy Voldemort's horcruxes, then Voldemort, and Snape if he can.  Hermoine and Ron tell Harry they're joining him in this effort. 

(Spoilers over.)

For those of you who chose to skip the above paragraph, I'll try to give you some idea of what happens in this book by comparing it to one of the earlier ones.  Imagine if you read the entire first Harry Potter book and it stopped at the moment he arrived at Hogwart's School.  In other words, we meet Harry and his nasty adoptive family, learn of his parents, his inheritance, etc.  We watch him shop for school supplies, get on the train, and arrive at school.  We learn about the Sorceror's Stone.  Then "The End".  That's about how this story feels to me. 

(Mild spoiler in this paragraph...) Harry learns about Voldemort and how/why Voldemort has survived Harry's past effort to kill him.  He's given more or less the instructions he needs to know in order to be able to get rid of Voldemort forever.  Then the book is over.  No confrontation with Voldemort.  Not even an actual APPEARANCE of Voldemort in the entire book, just other people talking about him.

Personally, this book says to me that one or both of two things must be true.  Either J.K. Rowling found herself under editorial pressure to get a new Harry Potter book out RIGHT NOW and essentially sliced off the introduction to the book she was PLANNING to write, tacking on a quick "shocker" twist and ending the story.  So what if it doesn't really tell a coherent story?  If that wasn't the motivation, then it must have been that she simply wanted to drag this story line out over a number of books so that she could sell several more (because at this slow, plodding rate it's going to take several books to finish the plot she's laid the groundwork for in this book).

In a nutshell, it was an "interesting" book, but the pace seemed extremely slow to me until the last two chapters, when it picked up very abruptly, then ended without really resolving the issues that it spent 28 chapters setting up.  The author's tendency to stop mid-conversation or mid-action to describe the room, its furniture, the view out the window, etc., was disorienting and distracting.  Still, the book did a good job of showing young Harry beginning to "come of age" and assert himself.  It also lays the groundwork for what could be a good story in the next book (which annoys me because I thought THIS book would tell that story).  Not the best book ever, but not the worst either.  I'd rate it maybe a 6 on a 1 to 10 scale (with 10 being excellent).  To be honest, most of that 6 comes from the good stories told in the past books/movies.