This is an interesting counterbalance to many popular science reads which affirm atheistic interpretations of neurological, biological and data from various psychological and research studies.
The narrative will please readers possessing spiritual belief, as it counters those of popular non-believers such as Dawkins, but in tone I found it to be more skeptical and agnostic about the conclusive findings of research such as the God gene or neurological scans of the brain activity of believers. It is much less the case that the author is affirmatively theist or spiritualist than they suspend judgement and present the evidence.
The book ranges across a number of topics, including neurology and biology (particularly with reference to stigmata as an exception to the rule that spiritual experiences are in the mind), drugs and neurotoxins in relationship to spiritual experience, sex and spirituality (which was disappointingly short and focued upon tantric sex and celibacy pretty much to the exclusion of anything else) and finally some good chapters on consciousness which dealt with Cartesian philosophical ideas.
Style and pace within the book are good, the narrative is interesting but now and again Foster lapses into a sort of pop journalistic sound bite exercise which I found a little distracting. So while reading and throughly enjoying insights on topics such as memetics (which Foster suggests can explain dissemination of ideas at best but not origins) I felt that Foster could spoil it by insisting on choosing to try to make a joke at just the wrong moment.
A good spiritual and pop science fusion read for those who read either genre or both, although not entirely original for anyone who has read about theories such as Julian Jaynes Bicameral Mind, neurological findings leading to the invention of a "God helmet", the God gene, the spiritual centres of the brain and similar topics. It is a good synopsis though.