From NetFlix:

Something is amiss in the sleepy California hamlet of Santa Mira. Initially, Dr. Miles Bennell (Kevin McCarthy) dismisses reports from the citizenry accusing friends and family of behaving like automatons. But the doctor soon makes a startling discovery. Extraterrestrials capable of replicating humans and assuming their identities have invaded Santa Mira. It’s up to Bennell to sound the alarm and almost single-handedly battle the alien forces.

Suppose you could trust no one around you, could you survive ? Of course, wartime spies are somewhat in that position. But this story is a famous extreme example. As an experiment in film comparison (which I also did with True Grit (1969) and True Grit (2010)) I decided to watch at least two if not three versions of this film.

For those of you too young to remember, Kevin McCarthy played many roles in the 1960 TV series “Twilight Zone”. Dana Wynter (the female lead) played Eva Wainwright in the 1966 TV series “The Man Who Never Was”.

What makes this film seem old ?

• Black and white
• Real orchestra music composed by Carmon Dragon that seems corny by today’s standards.
• Precious few special effects except for the pods bursting open
• The actors themselves actually had to run on streets and hills
• Unfortunately in this version, the ending is a terrible cop-out

Following is an excellent review that I found in IMDB attributed to someone billed as InfoFreak:

‘Invasion Of The Body Snatcher’s is my favourite 1950s science fiction movie alongside ‘Forbidden Planet’. Both are very different movies. ‘Forbidden Planet’ is arguably the first SF blockbuster, an intergalactic adventure, in colour, with a large budget and impressive special effects. ‘Invasion Of The Body Snatcher’s is a smaller movie, a low budget black and white paranoid thriller that is a classic of its type. Many subsequent movies have been influenced by this one, and there have been at least two remakes (Philip Kaufman, Abel Ferrara), but it still takes some beating! Director Don Siegel is best known for tough guy crime dramas like ‘The Killers’ and ‘Dirty Harry’, but shows his versatility with this extremely effective and disturbing horror story. The legendary Sam Peckinpah had an uncredited hand in the script, and (keep an eye open for) a small cameo as a meter reader. Kevin McCarthy is terrific as the small town doctor turned hero. His performance is excellent, and made him a legend to SF and horror fans everywhere (he reprises it briefly in Kaufman’s excellent 1970s remake by the way). The lovely Dana Wynter leads a strong supporting cast, and buffs will get a particular kick out of seeing Carolyn Jones (a.k.a. Morticia Addams) and Whit Bissell. (‘I Was A Teenage Werewolf’, ‘Creature From The Black Lagoon’ and too many others to mention!) This movie has aged very well, much better than say, ‘The Thing From Another World’, and still stands as THE 1950s paranoid SF/horror movie. An absolute classic that I guarantee still packs a punch! Highly recommended!

Have fun!