Harry Potter and the Half-Blood Prince
The latest installment in the Harry Potter series takes on even darker tones as J. K. Rowling continues to spin her web of mystery around the conflict between Harry and Lord Voldemort. The story opens with a meeting between Snape and several Death Eaters, discussing a plot that involves Draco Malfoy, in which Snape involves himself by making an unbreakable pledge. What the plot is remains a secret until the end of the book, however, there are several clues given throughout the book.
Harry's distrust of Snape is taken to a new level, as is his conflict with Malfoy. Harry has been consistent in his suspicions of Snape, and is constantly put down, as Dumbledore completely trusts Snape. This causes one to wonder if Harry is the proverbial "boy who cried wolf" or has he got Snape's number.
As for the Half-Blood Prince, and his role in the story, there is more there than meets the eye, as Harry embarks on a darker side of the magic world when he is given a copy of an old text book that belonged to someone who called himself "The Half-Blood Prince." This also provides conflict between Harry and Hermione, who is always suspicious of things that appear to be too good to be true or potentially dangerous. Her constant warnings about the book, and the question of who the "Prince" is sets the stage for revelations later in the book, when we learn who the mysterious "Prince" is. (Spoiler: it is not the obvious guess.)
This is a great book for nighttime reading if you don't mind losing a lot of sleep, as you will find it very difficult to put down, especially when you reach the point where Harry accompanies Dumbledore on a quest.
Harry Potter and the Half-Blood Prince will also leave you hungry for more, with expectations as to what will develop in the seventh installment, whenever that will be published (which isn't soon enough).