Typical of British movies of this genre, this one uses all the dark techniques. A decent plot that explores greed and human frailty, from both ours and an alien's outlook.

John Lawrence (Robert Clarke), a newspaper reporter who was stationed in England with the Army Air Corps during WWII, gets a tip from his old squadron’s meteorologist Professor Elliot (Raymond Bond) that a rogue planet is approaching earth. (This rogue planet scenario was probably borrowed from the George Pal movie When Worlds Collide released in the same year.) Lawrence visits Elliot in Scotland where he has established an observatory in an old castle. Lawrence finds that Elliot’s daughter Enid (who had a crush on him during the War) is now grown, very attractive and still has a crush on him. He also discovers that the professor’s assistant is the American Dr. Mears (William Schallert), a man with a dubious reputation.
Lawrence and Professor Elliot discover that Planet X is not only inhabited but has sent one of its residents to the Scottish moors. Lawrence and Elliot try to communicate with the alien but fail. They turn the task over to Dr. Mears who is only interested in obtaining information from the man from Planet X for Mears’ own enrichment.
The fog and the old castle set an ominous mood for the movie. The plot, however, is a both confusing and confused. Is this alien intended as a vanguard of an invading force or just an observer justifiably angered by the actions of a cruel and greedy earthman? Enid is uncertain of the spaceman’s motivation even in the final scene. She thinks he meant to be helpful, but I’m not so sure. I found the movie to be science-fantasy ’50’s fun.
What is truly amazing about The Man for Planet X is the budget. According to Internet sources, the film producer Jack Pollexfen once said that the original budget was $38,000, but evidently his free-spending director Edgar G. Ulmer eventually required $41,000 to complete the project. A dollar went much further in ’51 than today, but that that amount is ridiculous. Many of the sets in the film had been made for the ’48 movie Joan of Arc.

An absolute classic !
Great acting from all the principals.
Incredibly atmospheric as the heroes stalk through the fog bound moors of Scotland in search of the "boogy" from out of space !
I believe this is also the first time an alien visitor landed with peacful intentions, only to be turned against mankind by the actions of an evil Earth man.
Great to watch on a stormy night !

Great eerie sci-fi movie with its own atmospheric mystic. I remember watching this movie when I was a kid - scared me then - oh well. Was glad to be able to watch it again......memories.

Just a good movie, love the dark creepy parts of the film as well as some of the funny parts...a great movie for it's time.

this movie has an eerie sort of them with the fog and mohers setting a little creepy but the alein is not very scary.i saw this when iwas 6yrs old and the only thing that stood out in my mind was the setting not the alein,other wise its a good movie i watch it often.i like watching old sci-fi movies.