Cop & Robber, my new crime-thriller for 10-14 year-olds, has a book soundtrack that I listened to over and over again as I wrote. I tried to find songs that felt good and that captured the tone of the story. The music put me in a certain mood and that mood tapped me back in, even if it had been a week, a month or a year since I last worked on it. My work-in-progress, Scar Town, was started in 2009 and every time I return to the story I listen to the music which takes me back to the…