Existential Children's Books?

Here's a quote from an editorial in the May 2005 issue of School Library Journal called "The Big Questions" by Donna Freitas, a professor of religion:
Stories allow us to become explorers of religion, tantalizing us up the stairs to that locked door, that forgotten chest, the jeweled gowns at the back of the closet, hidden behind the stuffy, woolen coats. These stories have the power to move us from one place to another, to tear open the surface of tradition to a deeper, more primal place. A children's story opens the door to religious contemplation like nothing else can.
Agree? Disagree? Which children's books do YOU think "open the door" to religious contemplation (apart from the obvious ones written by Lewis, Pullman, and Tolkien)?