Also, according to that same pocket guide, the movie Alien plagiarized the 1950 novel "Voyage of the Space Beagle" by A.E. van Vogt. Like with Ellison, the producers of Alien settled out of court, to avoid losing a ton of money. I was able to verify it on Alien's Wikipedia page: "Van Vogt actually initiated a lawsuit against 20th Century Fox over the similarities, but Fox settled out of court." Several years ago, I read "Voyage of the Space Beagle" and verified for myself the similarities with Alien. Anyone that has a high opinion of Ridley Scott's "Alien" needs to read "Voyage of the Space Beagle" and get the real story, which is considerably superior to the movie.
So, two of the greatest movies from my childhood (Alien, Terminator) are heavily based on previously written material and were not original, with the exception of H.R. Giger's art in Alien (which won an Oscar for him). This problem has got my noodle boiling and brewing and makes me wonder: just what in Sam Fucking Hell is original?
Here are some potential candidates: Moon, District 9, Predator, Robocop, Dark City, Event Horizon and Pandorum. Predator may seem like a stretch, since there is nothing original about an alien hunting humans, but the way it was handled simply does not remind me of any of the science fiction I have read.
It's easier for me to think of science fiction movies that are not original. Here are some that are based on previously written material but did not plagiarize, like Alien and Terminator:
Planet of the Apes - Modified version of the novel by French author Pierre Boulle.
Blade Runner - Heavily modified version of the 1968 novel "Do Androids Dream of Electric Sheep?" by Philip K. Dick.
Total Recall - Heavily modified version of the 1966 novelette "We Can Remember it For You Wholesale" by Philip K. Dick.
Minority Report - Based on the 1956 novelette by Philip K. Dick.
A Scanner Darkly - Based on the 1977 novel by Philip K. Dick.
The Adjustment Bureau - Based on the 1954 novelette "Adjustment Team" by Philip K. Dick.
The Time Machine (1960), The Time Machine (2002) - Based on the 1895 novel by H.G. Wells. Neither version follows the novel exactly and leaves out the final observations of the future.
The War of the Worlds (1953), War of the Worlds (2005) - Based on the 1897 novel by H.G. Wells.
The Day the Earth Stood Still (1951), The Day the Earth Stood Still (2008) - Based on the 1940 short story "Farewell to the Master" by Harry Bates.
The Thing (1951), The Thing (1982), The Thing (2011) - Based on the 1938 novella "Who Goes There?" by John Campbell.
Mimic - Based on the 1942 short story of the same name by Donald A. Wollheim.
The Thirteenth Floor - Based on the 1964 novel "Simulacron-3" by Daniel F. Galouye. It has been published under the variant title "Counterfeit World".
Starship Troopers - Very loosely based on the 1959 novel of the same name by Robert Heinlein.
Logan's Run - Based on the 1967 novel of the same name by William Nolan and George Clayton Johnson.
Westworld - Based on the 1970 novel "Six-Gun Planet" by John Jakes.
Jurassic Park - Based on the 1990 novel of the same name by Michael Crichton. Also shares considerable similarities with the 1969 novel "The Parasaurians" by Robert Wells.
They Live - Based on the 1963 short story "Eight O'Clock in the Morning" by Ray Nelson.
Millennium - Based on the 1977 short story "Air Raid" by John Varley.
Waterworld - Shares similarities with the 1973 novel "Candle in the Sun" by Robert Wells.
Star Trek (entire series and all movies) - Basic idea came from the 1950 novel "Voyage of the Space Beagle" by A.E. van Vogt.
Freejack - Based on the 1959 novel "Immortality, Inc." by Robert Sheckley.
The Hunger Games - Although this movie is similar in premise to the Japanese movie Battle Royale, the major plot twist is similar to the 1965 novel "The 10th Victim" by Robert Sheckley. In fact, the similarity is extreme and I would say that "The 10th Victim" is a basis for the movie. If you liked The Hunger Games, then, right now, start looking for the The 10th Victim and read it as soon as possible. You will be happy.
The Matrix - The 1962 short story "Cocoon" by Keith Laumer shares similarities. Also, the 1970 novel "Matrix" by Douglas R. Mason looks eerily similar, based on the cover art. I have not yet read "Matrix", so I can't deny or confirm the similarities.
The Matrix is also probably based (I haven't read it yet) on the novel Simulacron-3 by Daniel F. Galouye. Again, take a look:
I have one more thing to say on this topic and it is not something that is easy to find. Do you remember the liquid metal terminator from Terminator 2? Do you remember the scene in the hospital where it was hiding on the floor and then killed the security guard after he got coffee? A.E. van Vogt created a liquid metal monster in his 1940 novelette "Vault of the Beast". Here is an excerpt:
"With a metallic hiss, almost a sigh, the creature dissolved, looking momentarily like diluted mercury. Then it turned brown like the floor. It became the floor, a slightly thicker stretch of dark-brown rubber spread out for yards."
Eventually, a man walks over the creature and it rises off the floor and copies his shape, just like in Terminator 2. Keep in mind that this was written in 1940, a full 50 years before Terminator 2. The similarity to the liquid metal terminator is staggering and I would suspect that Cameron stole the idea from "Vault of the Beast".