The Awakening & The Struggle by L. J. Smith (The Vampire Diaries #1-2)

The Awakening: Elena Gilbert is used to getting what she wants, and she wants the mysterious new boy at school, Stefan. Then she discovers he has a twin. But the brothers are hiding a deadly secret - a secret that will change Elena's life for ever ...

The Struggle: Elena is torn between her boyfriend, Stefan, and his brother, Damon. But these brothers hide dark secrets and a tragic past that threatens them all. Damon wants to lead Elena astray - and he'd rather kill Stefan than let him possess her ...