"The Shadow Out of Time" indirectly tells of the Great Race of Yith, an extraterrestrial species with the ability to travel through space and time. The Yithians accomplish this by switching bodies with hosts from the intended spatial or temporal destination. The story implies that the effect when seen from the outside is similar to spiritual possession.

Howard Phillips Lovecraft was an American author of fantasy, horror and science fiction.

He is notable for blending elements of science fiction and horror; and for popularizing "cosmic horror": the notion that some concepts, entities or experiences are barely comprehensible to human minds, and those who delve into such risk their sanity. Lovecraft has become a cult figure in the horror genre and is noted as creator of the "Cthulhu Mythos," a series of loosely interconnected fictions featuring a "pantheon" of nonhuman creatures, as well as the famed Necronomicon, a grimoire of magical rites and forbidden lore. His works typically had a tone of "cosmic pessimism," regarding mankind as insignificant and powerless in the universe.