Stephenie Meyers, yes, the author of the Twilight novels, reveals on her blog:
There was this one song by one of my favorite bands—it was such an amazing encapsulation of Edward’s mindset throughout Twilight, the despair and the hope and the despair again. The joy of first love plus the sure knowledge of impending tragedy. Perhaps because it was such a specifically Edwardian song, it never found a place in a Bella-centric movie. So it just sat there, being perfect for a story that was only in my head. The band never released the song. It only existed on an old submissions CD and my personal Midnight Sun playlist.
I’ve been listening to this song for a decade, all by myself.
When I realized that Midnight Sun was actually going to happen, that I was going to be able to finish it, my mind quickly turned to the playlist. There was pruning to be done, adding, subtracting, searching for songs that captured what I needed… but then this big problem. It wouldn’t be the Midnight Sun playlist without THE song. Which didn’t officially exist.
Skip to the happy ending: with an assist from Alex the Amazing, I was able to get in touch with the band and to my great joy, they were willing to help out. So here is THE song. I hope you love it as much as I do, though I’m not sure that’s possible. From the very excellent band Motion City Soundtrack, I give you Crooked Ways.