In this thought-provoking book, Dennett seeks to subject religion to the examination of scientific inquiry.  The questions he raises include whether or not religion improved our evolutionary fitness in the past, and whether religion has a more positive or negative impact on our lives today.  While he only briefly addresses the issue of cults, many of the issues he discusses about the human relationship to religion in general will be helpful for people seeking to understand the dynamics of cults.  The book raises more questions than it answers, but it makes a compelling argument for applying critical thinking to matters of faith, and will give readers seeking to expand their own understanding of religion a lot to work with.