I wrote this on my school's little wiki page:
Stephenie Meyer's phenominal Twilight series (which includes Twilight, New Moon, Eclipse, and the upcoming 08/02/08 release of Breaking Dawn) has been praised an awarded on several accounts. A couple awards include receiving New York Time's Editor's Choice, Publisher's Weekly Best Book of the Year. It also has been translated into 20 languages. The story begins about a girl, Isabella Swan, who moves from big city Pheonix into small town Forks with her father. She finds out that in Forks, everybody knows everything about everyone, especially when you're the Police Cheif's daughter. But her life is turned upsidedown when she meets Edward Cullen, the most handsome guy at school. Or should I say, the most handsome guy anyone has ever laid eyes on. But as she grows closer to him, Bella learns some shocking secrets about him and his family. You will definetly fall in love with this dark beauty-and-the-beast romance, I know I did!
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Now with more info, yes the Cullens are vampires. Also her best friend, Jacob Black, is their enemy. A werewolf. It all makes more sense if you read it.