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 Soviet Union and China remain a single bloc dominated by Moscow, and the sharp Sino-Soviet split of the late 1950s never happened.

Although they are considered not habit forming they do produce a mild euphoria, but mostly used as they can stretch out the users subjective perception of time, 'by a factor of ten or more'.

For example, in the last scene, a space warship is sent on a twelve-year trip to Titan, with not only life-support for a large crew, but also enough armaments to confront an entire world on its own.

The territory of the United States is divided into numerous transmission blocks, which receive television broadcasts from their neighbors and relay them onwards.

Its creation was never authorized by Congress and its existence is kept secret, being funded by sums diverted from innocuous sounding items in the budget.

Unlike the clearly demarked spheres of the FBI and CIA, the Section carries out extensive espionage in Soviet territory, but also conducts operations inside the United States.

The Army prepares a counterattack in the most heavily infested areas, planning to take over most broadcast centers and reveal the truth to the local residents.

They return to work and discover that people are now required to be practically naked as the slugs learned to attach themselves to other body parts.

Learning that the disease kills slugs faster than their human hosts, the authorities adopt biological warfare and release infected apes into enemy-held territory.

This edition contained material that had been cut from the original published version, because the book was deemed to be too long and controversial for the market in 1951.

Hero Sam penetrates the contaminated area, brings a 'master' back—a gelatinous gray mass which attaches itself to a soldier's body and controls his thought processes.

[6]The Brain Eaters, a 1958 science fiction film directed by Bruno VeSota, bore a number of similarities to Heinlein's novel.

Similarly, in the story line begun in the Star Trek: The Next Generation episode "Coming of Age" and completed in "Conspiracy", aliens from a faraway sector invade the bodies of high-ranking Starfleet admirals in an attempt to compromise the command structure and spearhead an invasion of Earth.

Also in the plot of the 1956 What Mad Universe by Fredric Brown—as in that of Puppet Masters—police and vigilantes ruthlessly shoot down anyone suspected of being controlled by the book's invaders from space.

Kenneth Von Gunden's novel Star Spawn[9] takes up the basic premise of The Puppet Masters and transfers it to a Medieval setting.

Extraterrestrial parasites able to take over the bodies of humans and control them invade Medieval England and embark on conquering it, castle by castle—and are eventually foiled by the highly resourceful Friar Gregory and his friend Sir Morrough the Knight.