The Zen of Oz : Ten Spiritual Lessons from Over the Rainbow

From a review of this book at Amazon:

We are Dorothy. Prodigal sons and daughters venturing out into the world on our own only to find out that there is no place like home. That the Wizard can't really give us anything we don't already have. That there is an inner spark of the Divine within each of us. That the Yellow Brick Road is an inner path that leads to the great beyond and that each of us must make the journey for ourselves. To realize that no matter where we are we are already over the rainbow for we make the rainbow. That life is a great mystery and that we are the greatest mystery of all. That life is full of wonder and joy, as well as pain and sorrow. That as Pierre Teilhard de Chardin said, 'We are not human beings having a spiritual experience. We are spiritual beings having a human experience.'

There's also a broader article discussing The Yellow Brick Road as Spiritual Journey here

Remember, there's no place like Om

(sorry, I couln't resist)