The author of this book, a Unitarian Universalist pastor who had been raised Mennonite, believes that we have outgrown the concept of a supernatural God, so we no longer need one, yet we still need religion to give us a sense of common community and ethics and morality.
He advocates religion without God. He posits that since religion has always explained the unexplainable, and we now have science to do that for us, the concept of a supernatural God, one who is inconceivably born of a virgin and who is omnipresent and omniscient, is an unnecessary and outmoded one. In his view, we are brought together by rituals and we need those rituals to give us a sense of community, gratitude and ethics, and we can do that without a supernatural God.
I disagree. I would rather have God without religion than religion without God.