Richard Sharpe Shaver (b. 1907 Berwick, Pennsylvania, d. 1975 Summit, Arkansas) achieved notoriety in the years following World War II as the author of controversial stories which were printed in science fiction magazines, (primarily Amazing Stories). The controversy stemmed from the fact that Shaver and his editor/publisher Ray Palmer claimed Shaver's writings, while presented in the guise of fiction, were fundamentally true.

Shaver's stories were promoted by Palmer as "The Shaver Mystery". Shaver wrote of tremendously advanced pre-historic races who had built cavern cities inside Earth before abandoning Earth for another planet. Those ancients also abandoned some of their own diseased offspring here, who degenerated over time into a population of mentally impaired sadists known as Dero--short for detrimental robots. These Dero still lived in the cave cities, according to Shaver, kidnapping surface-dwelling people for meat and using the fantastic "ray" machines that the great ancient races left behind to project tormenting thoughts and voices into our minds. Shaver claimed first-hand knowledge of the Dero and their caves. There is reported to be an obscure connection between the Shaver Mystery and the German Thule Society. Both Shaver and Palmer are said to have been in contact with a former Bavarian Gauleiter who was also a member of the occult society.

Between 1945 and 1949, letters poured in attesting to the truth of Shaver's claims (tens of thousands of letters, according to Palmer): the correspondents, too, had heard strange voices or encountered denizens of the hollow Earth. Fred Crisman, later to gain

In the 1960s and 70s, now living in obscurity, Shaver looked for physical evidence of the bygone pre-historic races. He found it in certain rocks, which he believed were "rock books" that had been created by the great ancients, and embedded with legible pictures and texts. For years he wrote about the rock books, photographed them, and made paintings of the images he found in them to demonstrate their historic importance. He never succeeded in generating much attention for his later findings during his lifetime, but in recent years, there have been exhibits of Shaver's art and photographs.

Shaver's Dero have also appeared in SubGenius mythology and are prominent in the work of artist Jermaine Rogers. The relative success of "The Shaver Mystery" in acquiring adherents from science fiction fandom may have influenced L. Ron Hubbard to invent Dianetics and promote it via SF magazines. The Japanese horror movie Marebito (2004, dir. Takashi Shimizu), also references Shaver's work and the Deros.