For over thirty years G. N. M. Tyrrell devoted himself to the study of psychical phenomena. Originally published in 1954, in his last book, written just before his death, he probes as deeply as possible into the meaning of the results of psychical research. He believes that paranormal phenomena are not isolated occurrences due to the exceptional gifts of a few unusual persons but the result of capacities which all human beings possess, though in widely varying degrees.

After an introductory chapter on Psychology and Psychiatry, the chief psychical phenomena - extra-sensory perception, mediumship, apparitions, etc. - are discussed and illustrated. Then follows a general criticism of current attitudes towards the subject. The book ends with two chapters arguing that the normal and paranormal are one and suggesting a pathway to religion.