Developmental psychologist and anthropologist Justin L. Barrett presents a theory that we are predisposed to believe in God from birth. It all begins in the brain. Infants, under the sway of powerful internal and external forces, make sense of their environments by imagining a creative and intelligent agent, a grand controller who makes the sun shine and the night fall. In the chaos of childhood, where so much is out of the child's control, this belief in a morally good creator can bring tremendous comfort and calm. A child's world is then filled with beings who intentionally act upon the environment, maintaining order. Summarizing scientific experiments conducted with children across the globe, Professor Barrett illustrates the ways human beings have come to develop complex belief systems about God's omniscience, the afterlife, and the immortality of deities, and shows how this underlies all of the major world religions, uniting them under one common source.