I find Half-Blood Prince to be highly interesting, because it deals with the construction of memory. It takes us to fascinating places in the mind that transcend the castle walls. I had friends mourn that we had moved away from the world of Quidditch and castle exploration, but I didn’t. To me, the series matured as Harry did, and we became immersed into the adult wizarding world as Harry did.
This time, Harry finds a Potions textbook with the inscription claiming ownership by a “Half-Blood Prince,” which he finds fascinating. Simultaneously, he has been asked to take private lessons with Dumbledore, all while trying to avoid being “collected” by new Potions professor, Horace Slughorn. In his lessons, he and Dumbledore travel backwards in time via memory, to figure out the origins of Lord Voldemort, aka Tom Marvolo Riddle, and how best to defeat him.
The novel ends rather shockingly (although I was spoiled to the ending the first time I’d read it, which made me so angry). I won’t go into it here for the handful of you who have not read, but it still takes my breath away. Of course, knowing what I do, little clues have been planted all along to make me marvel at the way Rowling had envisioned her series. Half-Blood Prince sets up the final book quite nicely, and we didn’t have to wait ten years for it, either!