The Vampire Diaries: The Struggle by L. J. Smith

Torn between two vampire brothers

Damon: determined to make Elena his, he'd kill his own brother to possess her.

Stefan: desperate for the power to destroy Damon, and protect Elena, he gives in to his thirst for human blood.

Elena: the girl who can have anyone finds herself in the middle of a love triangle . . . one that might turn deadly.