As we all know, Adele's musical peak with 21 is unlike anything we've seen in a very long time commercially speaking. It's easily arguable that it might be the most successful album ever released. With "Hello" and its beyond remarkable success, Adele has proven to be more than just a fluke. She is easily the most respected artist around and by far the most successful one too.  Her universal appeal comes from her soulful, strong, and beautiful voice and relatable, stripped down music. She's all