The puppet masters

The Puppet Masters is a 1951 science fiction novel by American writer Robert A. Heinlein, in which American secret agents battle parasitic invaders from outer space. It was originally serialized in Galaxy Science Fiction (September, October, and November 1951). The novel evokes a sense of paranoia and Heinlein repeatedly makes explicit the analogy between the mind-controlling parasites and the Communist Russians, echoing the prevailing Second Red Scare in the United States. The book takes up the then common theme of sightings of flying saucers, the plot assuming that the "saucers" seen in the 1950s were part of a preliminary reconnaissance of Earth, carried out by the extraterrestrials in preparation for a full-fledged invasion sixty years later.