The Los Angeles Review of Books offers a review of two books on Ray Palmer, the Shaver Mystery, and pulp-esoteric publishing of the 1940s–50s: The War Over Lemuria and The Man from Mars : Ray Palmer’s Amazing Pulp Journey.
From the review:
Of course, the underground worlds of Richard Shaver did not spring full grown from his brain, no matter how fevered it might have been. Subterranean adventure has long been a staple of science-fiction. Even more to the point, the belief in the existence of subterranean civilizations itself has a long history, and not just among the ancients who believed in one form or another of an underworld abode of the dead. Indeed, there are other instances in which fictional stories about the underworld have been regarded by some readers as revealing a hidden, sometimes religious truth. The Shaver Mystery, it turns out, is not without precedent. John Cleve Symmes’s hollow-earth novel Symzonia (1820), Edward Bulwer-Lytton’s Vril: The Power of the Coming Race (1871), and Willis George Emerson’s The Smokey God (1908) are all examples of fictional tales of underground civilizations that have been treated as true accounts and the source for religious belief by some members of the Theosophical and occult communities. Shaver’s stories are darker than the similar works that preceded them, but Palmer’s claim that Shaver’s tales contained truths about the hidden world under our feet is part of a long tradition.
Ray Palmer went on to found Fate magazine, which has done several retrospective articles on the Shaver Mystery over the years. Until 1988, Fate was published in Chicago, which just adds to that whole “occult Chicago” meme. (See also the work of occult journalist Brad Steiger.)