Dramatic advances in neuroimaging technology now permit researchers to observe the activity of brain systems that regulate religious belief and behavior, and this research forms the heart of the book.

Communion with an ethereal God through prayer and contemplation is obviously important to those who seek divine help. But how do we know that such supplications demonstrate a genuine trust in God, rather than an ingrained habit? Although the authors can't currently answer that complex question, they used neuroimaging technology to seek accessible data on the more fundamental problem - to identify the brain systems that process human/divine interaction.

The research design was simple: Locate people who have a strong belief in the efficacy of spiritual connection, and have had extended experience in seeking it. Compare their levels of brain activity when they are and are not spiritually engaged.

The book describes the results of studies with Buddhist monks during meditation, Franciscan nuns during prayer, Pentecostals during glossolalia (speaking in tongues), and an atheist with much meditative experience. What follows is a brief synthesis of key elements of the book's extensive non-technical report of the research and its implications.

The brain scans of the monks and nuns during contemplative states were similar. Both experienced a reduction of activity in brain areas that orient us in space and time. Here/there and past/present/future thus lost their normal meaning, and were supplemented by a sense of being at one with God (nuns) or the universe (monks).

Both groups also experienced increased activity in brain areas that regulate attentionÑnot surprising, because the subjects' contemplative activity was highly focused. Further, attention is a central element of problem solving, and prayer is basically a problem solving activity. The authors suggest that focused positive religious ritual creates an optimistic feeling that in turn enhances our sense of the validity of our beliefs.

The brain scans of the Pentecostal subjects who spoke in tongues (glossolalia) during what could be called a peak experience differed from those of the contemplative monks and nuns. During glossolalia, activity decreased in the brain areas that regulate attention, increased in the areas that regulate emotion, and remained constant in the orienting areas. The Pentecostals thus didn't lose their sense of self in search of God, but rather reported that they simply "gave themselves over to God" and allowed the experience to unfold as it would. Perhaps most intriguing, activity in their brain's language area didn't increase, which suggests that speaking in tongues might activate different circuits than those used during normal speech.

The researchers also studied an avowed atheist who had long engaged in meditative activities, and when meditating, often (and surprisingly) focused on the image of God depicted in Michelangelo's Sistine Chapel painting. Although he had conventional moral/ethical views, he disavowed any theological base for them.

His brain scans exhibited a reduction in orienting area activity during meditation that was similar to the monks and nuns, but no increase in attention area activity. His resting state attention area activity was higher than the monks and nuns, which might be explained by his very analytical personality.

The thalamus is a divided relay station between sensory input and cognitive analysis. All subjects in the study exhibited abnormal thalamic activation during resting periods, the left side being more active than the right. The authors suggest that the long term spiritual and/or meditative activity of these subjects may have permanently altered their normal perception of reality. In religious people, for example, spiritual feelings can thus become the norm. One nun said, "I feel God's presence every minute of the day."

In general, the research suggests that our sense of reality is powerfully influenced by the vividness of the experiences that shape our beliefs. Intense contemplative and peak experience activity alters normal brain activity, and extended focused spiritual activity can permanently alter the neural networks that maintain beliefs. This isn't surprising; because any learned information or developed skill does the same thing. What's important about this research is that it connects spiritual behavior to specific cognitive systems that then enhance the reality of a person's beliefs. Spirituality thus isn't a completely disembodied (soul, spirit) experience, as many believe. Further, each system of sacred/secular belief activates a unique pattern of neural activity that changes the way the adherents perceive reality.