The first chapter of book six is a rebirth from one of the chapters from the Philosophers Stone.
The Half-Blood Prince isn't Harry or Voldemort
There is some info that will be in the Half-Blood Prince that was originally placed in the Chamber of Secrets. There are some very releaving clues in the Chamber of Secrets about what will happen at the end of the series.
There will be a new Defense Against the Dark Arts teacher.
There will be a new Minister of Magic.
There will be a new Quidditch Captain.
We will learn about what happened to Wormtail.
Cho will no longer be Harry's girlfriend, however he will have some love in his life.
We learned about these three chapter titles: Chapter Two: Spinners End, Chapter Six: Draco's Detour, and Chapter Fourteen: Felix Felicis
We saw this small phrase from the book: "He looked rather like an old lion. There were streaks of grey in his mane of tawny hair and his bushy eyebrows; he had keen yellowish eyes behind a pair of wire-rimmed spectacles and a certain rangy, loping grace even though he walked with a slight limp."
Harry Potter will be in his 6th year of Hogwarts.
Harry will get his marks on his OWLs this summer.