Invasion of the Body Snatchers is the remake of 1956 movie by the same title and considered to be, by many fans, to be the definitive and the best version of the story.
The movie begins with images of plasmas from an alien world floating out into space towards planet earth. Then the rain comes and we see an odd organism growing on plants' leafs. Before too long, people start to act strange, they group and exchange plants, they act indifferent to their surroundings, they are emotionless, almost robotic. A group of characters who are not affected soon find themselves a minority in a world that is changing rapidly.
One of the greatest appeals of this movie is its socio-political resonance. It can be interpreted as a state of minority versus majority, us versus them and individualism versus social conformity. It shows how we try to turn the others into a version of ourselves because we can't tolerate the otherness. And maybe this is a universal common trait of all beings whether alien or human. Even though the commentary is about humans, it is actually alien organism that takes over human bodies (snatches human bodies - hence body snatchers).
The movie also questions how much we should sacrifice to achieve harmony in society. Should we preserve our individuality at risk of conflicting with other members of the society, or should we just join the majority, think like others, walk like others and talk like others do? Like all great science fiction movies, the story is social commentary on the state of the world. This is probably the reason why there are so many versions of this movie. And most recently in 2007, another version was made called "The Invasion" starring Nicole Kidman and Daniel Craig.
