Serling served in World War II as an Army paratrooper. His experience and trauma from his time in the war are reflected in the dark and moralistic tones of his writing. According to a Smithsonian Magazine article, it was from his paratrooping days that he came up with the name “The Twilight Zone.” The twilight zone is the moment the plane goes down and can no longer see the horizon.
After the show’s fifth season it was canceled, although Serling would claim that the cancellation was more a mutual agreement. He bemoaned the direction the network wanted him to go in, wanting more actual monsters and less parable. He discussed this in the last interview of his life in 1975.
“I think you can say more obviously in the framework of an honest-to-Christ contemporary piece so that you don’t have to talk in parables, in symbolisms and the rest of it, but this is not to say that you can’t make a point of social criticism using science fiction or fantasy as your backdrop. We did that on ‘Twilight Zone’ a lot, but there’s no room for that kind of subtlety anymore. The problems are so much with us that they have to be attacked directly.”
Besides attempting and failing to get a movie made, Serling was done with “The Twilight Zone” after its cancellation. Despite this, he left a permanent stamp on the American psyche and on the entertainment industry. And a big part of that is the eerie name that he pulled out of what were likely some of the darkest days of his life.