The air may seem clear enough, and fluffy white clouds on high seem innocent enough; but it is an arena in which parade extraordinary - if rare and transient - phenomena which are currently inexplicable. They are none the less real. The thunder god Thor is a powerful deity and it is from his strange and awesome kingdom that UFOs come forth to confront us.

This book puts forward an interesting theory about the link between geology, prehistoric monuments, the human mind and the appearance of UFOs, which grew on me during the second half of the book. It seems more likely than the ETH anyway. ( )