The plot has a Dr. Binnell arriving to town after a vacation and encountering a rash of people claiming that their relatives are no longer themselves. Later, these same people recant. Gradually, Binnell comes to believe that these people are controlled by aliens and that they are after him as well.

This film asks the questions: What if the people closest to you were suddenly different. What if they had some secret and evil plan? What if they wanted you to join them, even against your will? While the plot has these people's bodies possessed by alien pods from outer space, the screenplay may be a thinly disguised jab at cold war paranoia in the U.S., and the general belief that communists were around every corner and out to subvert the country. Since screenwriters as well as actors were blacklisted (see Woody Allen's "The Front") and lived in fear of losing their jobs during the cold war, any protest that a screenwriter made would have to be between the lines.

The "pod people" in this film don't act like the controlled zombies you would expect them to be, except in the group scenes. Taken one by one, they just seem to be bad tempered. Often they act quite human. More consistency for "pod people" behavior would have been an improvement, as well as greater contrast in personalities between those converted and those still alive.

Binnell, who has somehow remained single and unattached all these years, meets old flame Becky Driscoll, also unattached. They are a couple for the rest of the film. This begs the questions: Why does a sci-fi flick have to have a love interest subplot? Why can't Binnell and Becky be cast as happily married rather than just reunited long lost lovers? Is a relationship only considered interesting if it is brand new?

The studio wanted to soften the ending of the "Invasion of the Body Snatchers", so the put additional scenes at the beginning and end of the film. It can be argued that tampering with the director's concept ruins the film, but a three minute scene added to an eighty minute film cannot significantly affect its grade.

Petty criticisms aside, "Invasion of the Body Snatchers" is a good and original film that successfully explores the paranoia that sometimes lurks within us all.