Elvis Presley is the King of Rock and Roll.  He changed music forever.  It appears, though, that he may not have thought much of his actual abilities as a musician.  He was once quoted as saying:  "I don't know anything about music.  In my line, you don't have to."  He may not have known about music, but he knew how to drive the girls crazy and sell records.  And that is good enough for rock and roll.