The co-authors of the smash teen hit "Nick and Nora's Infinite Play List," discuss their new novels. Rachel Cohn's "Beta" is the first installment in a dazzling new science fiction series about teenage clones fighting for survival in a corrupt world. In "Every Day," David Levithan offers the impossibly delightful love story about "A," a spirit that takes over the body of a new teenager each day, and the girl he falls in love with over and over.