What happens when a person has a Clear, Vivid, ecstatic, transcendent religious or spiritual experience where they sense that they are being 'caught up' to God, or Spirit? Do they really encounter an unseen, intangible 'spiritual realm' that is Ultimate Reality and the Ground of existence? Why do some people who are diagnosed as 'mentally ill' claim to have such experiences? If a person persists in these kinds of beliefs, are they deluded, or even mad? Are they actually suffering from 'religious mania'? Are atheists correct in dismissing these experiences as merely 'psychological'? Or is it the atheists who are blind and deaf when it comes to Ultimate Reality? Drawing from personal experience and from over forty years of practical and theoretical engagement with spirituality and religion, as well as from approaches within psychology, author Robert Laynton explores these questions, not as a defense of religion or spirituality but as an exploration of experience on the edge of reason.