This is a series of personal experiences examined as if they were problems in detection. The author, who for a generation conducted archaeological investigations on behalf of the Cambridge Antiquarian Society and the University Museum of Archaeology and Ethnology, tells of some of the paranormal occurrences which have come his way and then pulls the tales to pieces in an endeavour to find out the meaning of each one. In the process various widely accepted theories, such as the Darwinian Theory of Evolution, have to be discarded; although they had formed the background of the author’s thought since childhood. The author comes to the conclusion that there is no such thing as the supernatural. Everything must conform to natural laws, although some of these laws remain to be discovered and formulated. He also suggests that there is another natural force, comparable perhaps to electro-magnetism, which is as yet almost unstudied. While retaining the right to change his ideas in the light of future evidence, he puts forward some possible hypotheses to account for the phenomena as they are at present understood.