The basic concept of this extraordinary motion picture, without the shadow of a doubt one of the great masterpieces of science fiction cinema, doesn't seem so original and shocking at first sight. There had already been movies which had shown aliens being able to control human beings, or even shapeshift into a convincing copy of them. However, in earlier motion pictures, the transformation was always reversible and the aliens remained something quite distinct and separate. They were always beings who could be identified and fought.

In Invasion of the body snatchers, the mysterious aliens completely destroy the minds of the unfortunate human hosts and to all extents become the human. Never before the release of this film has a horror of that magnitude been portrayed on a cinematic screen.

In the beginning of the film there is only a slight sense of uncertainty and foreboding. Why do a few residents of the quiet town of Santa Mira, California, believe that members of their family are not what they seem to be? Doctor Miles Bennell (Kevin McCarthy), at first does not give any weight to the accusations as the individuals in question seem completely normal. However, the more the good Doctor looks into the situation, the stranger things become and the more his doubts increase. Finally one night, the discovery of a body which is still "under development" finally erases all doubts once and for all.

The alien pod things seem to transform themselves into perfect cloned copies of the humans beside them, absorbing their personality and memories while they sleep. The original humans no longer awaken and the copies take their place, although they seem emotionless and almost zombie like.

It soon becomes evident that the copied humans are distributing the alien vessels everywhere they go throughout Santa Mira and in nearby cities, thus there is very little left for Doctor Bennell to do but to try and flee while making sure that he doesn't ever fall asleep. The original ending had the Doctor reaching a highway crying for help and trying to flag down cars, but none of the motorists take him seriously and speed on by. The studio, however, wanted a happy Hollywood ending so director Don Siegel was forced to shoot an epilogue where the Doctor explains the entire story to policemen who don't believe a word he says, until they by sheer chance intercept a truckload of the evil seed pod alien thingies.

Invasion of the body snatchers is a phenomenal and ground breaking science fiction movie, regardless of what ending is tacked onto it or not, due to its original concept of an alien creature who takes over your body while you are defenseless and sleeping. The film preys on the primal fears of the audience and even though it can be argued that this is not the best science fiction film of the era, few can dispute that it is by far the most refined and precise, as well as being one of the most unforgettable.

1956: Invasion of the body snatchers

Directed by
Don Siegel
 
Screenwriting by
Jack Finney (for the Collier's magazine serial)
Daniel Mainwaring (for the screenplay)

Cast 
 Dr. Miles J. Bennell - Kevin McCarthy
 Becky Driscoll - Dana Wynter
 Dr. Dan 'Danny' Kauffman - Larry Gates
 Jack Belicec - King Donovan
 Theodora 'Teddy' Belicec - Carolyn Jones
 Nurse Sally Withers - Jean Willes
 Police Chief Nick Grivett - Ralph Dumke
 Wilma Lentz - Virginia Christine
 Uncle Ira Lentz - Tom Fadden
 Stanley Driscoll - Kenneth Patterson
 Officer Sam Janzek - Guy Way
 Anne Grimaldi - Eileen Stevens