Movies have them, why can't books?

I've been writing my book for several years now and when I write I listen to music. There are several scenes in my series so far that have been greatly influenced by particular songs. Songs like Jenny Was a Friend of Mine by The Killers and Adele's Set Fire to the Rain. Adele's song actually inspired a scene for the second book in the series. I also listen to soundtracks to movies as well and a group that, much to my laughter, itunes categorized as soundtrack music, Two Steps from Hell.

Which leads me to my topic. There aren't a lot of soundtracks to books out there. I'm not talking about soundtracks to movies that were adapted from books and I have heard that some books do it but it's still a small amount. So I plan on making a list of the songs I listened to while writing my book, He Came Around the Corner. I also figured I could put on the list when the song came into play in the book or even when to listen to the song when someone is reading it.

I feel that if the music made that much of an impact while writing it then it would enhance the scene while reading it. When I had my friends read excerpts to give me feedback, I suggested they listen to the soundtrack to the Lord of Rings movies while they did. They said that some of the scenes were really more pronounced when the music was playing.

I'm sure there's some science behind this, I'm pretty sure it has something to do with stimulating different parts of the brain at the same time. I've also heard a lot of discussions on how music affects people which of course is fascinating. What I'm getting at though is, if the opportunity is there, why not enjoy the music?