About 90% of people have faith in a supreme being, but our yearning for the divine, and whatever it promises, involves a large divergence in mental states and behaviors. Some adhere to doctrine, supplication, and fastidious religious practices; others have a strong sense they are part of something greater and more universal. However, all religious and spiritual paths are mediated by complex brain networks. When different areas of the brain are stimulated, a person can have a variety of experiences, but there is no specific 'God spot' where stimulation enhances religiosity or spirituality. Functional brain imaging shows that there are specific areas of the brain that 'light up' when subjects perform certain religious activities, but imaging only provides anatomic correlations, not functional explanations. The Believer's Brain takes a step beyond these singular methodologies, providing converging evidence from a variety study methods of how humans' brain networks mediate different aspects of religious and spiritual beliefs, feelings, actions, and experiences. Although the book reveals how our brain is the home to the religious and spiritual mind, understanding this gift will not diminish our spirituality or our love or our belief in a supreme being, but will increase appreciation of the apparatus that mediates these mental states.