Paradoxically, in an age when the supernatural has largely been dismissed, the interest in spiritualism, faith healing and all sorts of clairvoyance right down to the astrologers of the popular press shows no sign of diminishing. This book describes how the methods and controls applied in the natural sciences have been directed to examining telepathy, communication with the dead, telekinesis, poltergeists and miracles. While these stringent tests expose much that is false or capable of straightforward explanation, they reveal that human beings do possess extra-sensory perceptions knows under the general heading of 'psi-factor'.