First off, this book is absolutely NOTHING like Twilight. I know it says on the cover that it is, but THIS IS A LIE.
I don't know why people compare this book to Twilight. There are no vampires, no werewolves, no "OMG swoon' moments, no shirtless Native American boys, and no sparkling.
This book would be more accurately compared to The Lovely Bones. In both books, we have a girl watching how her death affects people but is separated from them. However, in The Lovely Bones, Susie was killed right in the beginning and her family was left wondering what happened. In If I Stay, Mia's family is in a horrific car crash and she is watching herself from outside her body, seeing how her remaining family and friends react to her being in critical condition in the hospital.
Basically, the premise of the book is whether Mia wants to fight to survive despite grievous losses, or if she wants to pass on like her parents and little brother.
It's not an easy decision, and at first she doesn't know what's going on. She can't figure out why she's standing by her injured body and can't feel anything. But slowly she puts the pieces together. As various family members and friends come to the hospital, she watches their reactions and listens to what they say to her unconscious body. She sees the nurses and hears what the doctors say about her. She sees herself on the operating table. As she watches, she remembers her life. She thinks about the things she did with her family which she can never do again. She thinks about her accomplishments and dreams. She thinks about her boyfriend and her best friend. She thinks about a funeral she went to. She thinks about the birth of her brother.
The reader glimpses scenes from Mia's life interspersed with scenes of the hospital. The setting and the writing are done extremely well. If I Stay is a bittersweet book, very touching and heartfelt, but also hard to put down.
I think the only similarity I can find between this and Twilight is that they're both set in the Pacific Northwest. But they're not even the same state, so it's a very loose connection.
Oh, and guess what? There's a sequel now! Check it out!