Harry Potter and The Half Blood Prince is certainly the darkest of the books that has been filmed so far. The Death Eaters are at large- affecting the Muggle world as well as the magical one- and danger stalks the corridors of Hogwarts. If you're a fan of the films but haven't yet read the books you'll definitely want to avoid hearing what happens in this one before you go to see it- avoid all talk and spoilers as best you can.
It's the penultimate book in the series although the last book, The Deathly Hallows, is apparently to be broken into two parts for its appearance on the big screen.
I didn't take to the Potter tales when they first came out, and I ignored the films for some time too. In a way I'm glad that I did- I was able to read them all basically one after the other. They really are nicely written, the world is well developed and Harry, Ron, Hermione are great characters- along with a brilliant supporting cast. I've got to say that I'm pleased with the film adaptations too- and I'm very much looking forward to seeing this one on the big screen. So, after all that, here's the first trailer for Half-Blood Prince.