I heard a long time ago, from a friend who knew him personlly, the song was written about a ghost he encountered while on holiday. She troubled him, so much so, that he wrote a song about her, in a sense, to keep her and her memory alive. This song has touched the lives of many, probably because of the mystery of it and it's origins. Do we really want to know, who or what it is about? Or do we want to allow our imaginations to continue to speculate? If it is about a woman who now is 40 something so be it. But if it isn't....? Have fun, Cat always loved the spiritual.