Traditional item of sf Terminology for various surveillance mechanisms employing some kind of Ray that can penetrate most forms of matter, conferring the power of undetectable eavesdropping upon its operator. E E Smith uses the term throughout his Lensman series and seems to have coined it in the original magazine version of Triplanetary (January-April 1934 Amazing; exp rev 1948). Inevitably this Technology leads to a kind of arms race, with "spy-ray blocks" – as in First Lensman (1950) – countered by advanced rays tailored to penetrate such blocks, and so on. Isaac Asimov calls the device a "spy beam" in Foundation (May 1942-October 1944 Astounding; fixup 1951), which also features a "static field" countermeasure. Superman's "x-ray vision" is the equivalent of a built-in spy-ray which however is blocked by lead.
Real-world analogues of this imagined technology include radar and, more in keeping with the imagined scope of a spy-ray, the use of laser reflection from an external window to detect vibrations caused by sounds within. Another well-known sf device which generally includes the functions of a spy-ray as a subset of its capabilities is the Time Viewer. [DRL]
Previous versions of this entry