One River, Many Wells (Matthew Fox) (2001)
In his book, One River, Many Wells, Matthew Fox discusses his vision of the unity of the world's spiritual traditions. He believes that spirituality is no longer an option, but is the only way that we are going to survive as a species.
Fox uses the metaphor of God as a great underground river that no one can dam up, and likens the religions around the world to underground wells.
He tells us that when we confuse the river with the wells, we fall into conflict. To resolve this problem, we must distinguish between the spiritual source with which we are trying to connect and the particular traditions that we use to access the source.