Benford is writing within one of the most heavily worked traditions of science fiction — the story which expresses the fear that humanity may someday be replaced by another species, perhaps one which we ourselves are responsible for bringing into existence. Mary Shelley's Frankenstein (1818) is, in part, an early working out of this idea, as is H. G. Wells's The Time Machine (1895). Other early and influential examples of the theme include Karel Capek's R.U.R. (1921), which features the first fictional uprising of artificial intelligences against their masters, and his War With the Newts (1937), in which a race of not very successful but intelligent amphibians is first enslaved by humanity and then, learning human military techniques, conquers the planet. Capek's fiction, and the many similar stories which followed, can clearly be read as allegory. Behind the revolt of the robots lies the upper-class fear of the...