Voldemort is back. The problem is most of the Wizarding world doesn't believe Harry or Dumbledore. With a new Defense Against the Dark Arts teacher, about as evil as Voldemort, Harry and his friends have a dark year upon them. Hogwarts isn't nearly as enjoyable as it used to be.
This is my all time favorite of the series and the one I have read the most. I absolutely love many scenes in this book and still get mad every time that Sirius had to die. I love Dumbledore's Army, when Fred and George fly off on their broomsticks, when they go to the Ministry of Magic to fight at the end. It's all so good. And its long, but not one point do I ever get bored in this series.
I think if I had to point out one flaw in this series, its that Harry just doesn't develop as a character. He remains pretty much the same throughout the entire series. He never listens to advice, he gets angry, and he's so headstrong the entire time. I just wish he' grow up a little bit.