At the beginning of this book the author describes a frightening experience he had while pot-holing in Yorkshire. This experience, involving lights and strange sounds, was, one assumes, probably a combination of natural phenomena and subjective reactions. However, its effect on the writer seems to have made him an uncritical believer in a wide range of occult and other dubious claims (something which seems to happen quite often to those whose interest in the unexplained is aroused by odd personal experiences Arthur Shuttlewood and some close-encounter percipients provide other examples). As a result, in this book he argues for the existence of a world-wide tunnel network constructed by some mysterious lost science and supports his case by reference to 'evidence' such as the Von Daniken Ecuador caves hoax and the claims of pseudo-archaeologists such as H. T. Wilkins and Peter Kolosimo.
This is a pity, since much of the book is devoted to a straightforward history of the idea of underground races as it has been developed in legend, occultism and science fiction. He does not give detailed references and in some places relies on dubious secondary sources, as in the section on Hitler's alleged belief in underground races which consists largely of the endlessly rehashed quotes from The Dawn of Magic. (Incidentally, the alleged discovery of large numbers of 'Tibetans' in German Army uniforms in Berlin in 1945 is not evidence of Nazi interest in Tibetan magic, but merely of the widespread recruitment of Russian national minorities into the Wehrmacht.) However, he has clearly read widely and includes some interesting and original material.
Some of the material he cites enables one to come to other conclusions about the significance of the prevalence of beliefs in underground races. The underground race, living completely estranged from sky, sun and nature, has for some served as an anti-utopian future of the human race (e.g. H. G. Wells's The Time Machine and Fritz Lang's film Metropolis). In the children's novels of Allan Garner his characters stumble on underground races of dwarfs and wizards who provide images of absolutes of good, evil and heroism contrasting with the banality of everyday surface life. The malign underground beings, capable of evil interference in the life of surface dwellers, depicted in the writings of H P Lovecraft and Ray Palmer are a powerful symbol of violence and irrationality beneath the facade of civilisation. - Roger Sandell, from Magonia 9, 1982.