As a species, we have been killing ourselves by the millions in war after war throughout history. Now, finally, we have the power of knowledge to end forever, or at the very least drastically reduce, all this human slaughter. Freedom gives us the answer. Until all people everywhere enjoy this freedom, we must foster at least some freedom where none exists, to lessen mass killing by war.
Spirituality is a way of being in the world, a sense of one's place in the cosmos, a relationship to that which extends beyond ourselves. There are many sources of spirituality; religion may be the most common, but it is by no means the only. Anything that generates a sense of awe may be a source of spirituality. Science does this in spades.
This book may allow some people to overcome their fear of the vengeful, cruel God they were taught to believe in as children. It may allow more people to speak out when they hear religious leaders use their God to incite people to harm others. It may even allow more of us to admit, "I could be wrong."