Cast :

Michael Rennie ................. Klaatu
Patricia Neal ................. Helen Benson
Hugh Marlowe ................. Tom Stevens
Sam Jaffe ................. Dr. Barnhardt
Billy Gray ................. Bobby Benson
Frances Bavier ................. Mrs. Barley
Lock Martin ................. Gort
etc ...

The film is Robert Wise's cult classic of the 1950s, often credited with starting the boom of that decade's science-fiction movies.

Although sci-fi is, as a rule, intrinsically a funny genre, this movie is quite serious --like "2001: A Space Odyssey." Gort moves somewhat like Frankenstein's monster, probably because the man inside it has to cope with an oversize covering and elevator shoes. And near the end, Klaatu is resuscitated by Gort with machines that are like cat-scanners with ultrasound. Interesting plot follows, easy on special effects (good for the period), heavy on humanism and messages. 

Unusually fine film is a multi-layered document of 1950s malaise, especially cold war and freedom of thought. The shadow of McCarthyism is evidenced by the criticism of prejudice, and more subtly when Klaatu says in an interview: "I'm afraid, but in a different way. When I see people substituting fear for..." then a reporter cuts him off with a "Thank you, sir." 

One of the challenges was the Gort character himself. We knew we had to have some kind of suit that somebody could be in. This was before we had such a great number of 6'8", 7'2" basketball players, and we were searching all over for a very tall man, going to extra casting people and casting departments. Somebody remembered that the Grauman’s Chinese Theater had in those days a terribly tall doorman. He was 7'7" and we hired him to be in that suit. He was not a very strong man, and that suit was heavy. He could only stay in it for about half an hour at a time.

The eyes of the world converge on Washington, D.C. when a flying saucer lands on the capital’s mall. From inside the ship emerge an alien of human features, Klaatu, and an eight-foot-tall metallic robot, Gort. As he reaches inside his spacesuit for an object that turns out to be a gift for the president, Klaatu is shot by a soldier. Gort reacts by destroying all weapons in sight before being stopped by Klaatu, who is then taken to a hospital. 

The alien seeks a meeting with all the leaders of the world but is informed by a member of the White House staff that such a gathering would be unthinkable. Klaatu escapes the hospital and, in order to better understand the people of the Earth, takes a room in a boarding house under the name of Mr. Carpenter, befriending a young widow, Helen Benson, and her son Bobby. Klaatu hits upon the idea of delivering his message to the great minds of the world, and contacts the prominent Professor Barnhardt. In a non-violent demonstration of his powers, the alien stops all electricity on Earth for thirty minutes, but the display only heightens the hostility fomented against him by the government and the media. As he tries to reach his spaceship, where Barnhardt’s peers will soon join him, Klaatu is mortally wounded by the military. Acting on his instructions, Helen seeks Gort’s help. The robot retrieves Klaatu’s body and brings it back to life. 

Before leaving, Klaatu tells the assembled scientists that other planets have come to enjoy peaceful coexistence because of the vigilance of an army of robots like Gort and that Earth will face obliteration if it carries its belligerent ways into space.