It's only been seven years since "Tik Tok" introudced us to a pop singer who brushed her teeth with a bottle of Jack and partied until the break of dawn. These days, Kesha has dropped the ill-advised dollar sign from her name and (mostly) shed her party girl image. Released in the wake of ongoing lawsuits against her former producer Lukasz “Dr. Luke” Gottwald, Rainbow never addresses the tumultuous controversy head-on, but the subtext is there. From a duet with Dolly Parton to a jam with the Dap-Kings, the album is a showcase of Kesha's talents that purposefully (and joyfully) moves beyond her past. "Thrift Shop" rapper Macklemore joins her.