Science fiction has often been considered the literature of futuristic technology: fantastic warfare among the stars or ruinous apocalypses on Earth. The last century, however, saw through John W. Campbell the introduction of "psience fiction," which explores themes of mind powers--telepathy, precognition of the future, teleportation, etc.--and symbolic machines that react to such forces. The author surveys this long-ignored literary shift through a series of influential novels and short stories published between the 1930s and the present. This discussion is framed by the sudden surge of interest in parapsychology and its absorption not only into the SF genre, but also into the real world through military experiments such as the Stargate Project.