Does anyone need an introduction anymore to this great series? In the beginning Desilu said yes to the budget and schedule of Roddenberry only because there were many space stories being pitched and picked up in the mid-sixties, and this was going to be theirs. NBC used Star Trek to compete with Lost in Space, which was already on CBS the year before.
NBC being the all color network made the series very high key in lighting and primary-colored in the uniforms and the instrument displays, to better sell color TV at the time.
There were so many innovations shown on the screen from Dr.McCoy's diagnostic helpers to the auto door movements to hand communicators, transporters, phased light weapons, all of which impressed viewers. Added to that, they all seemed like they really worked!
People have said that Star Trek was the first to show an alien working harmoniously on a space crew and this is not fully true. You might laugh now, but in 1950 there was a very popular, well written, well acted radio and TV series called "Tom Corbett, Space Cadet" that had that very element working for it. Nothing much was very ground breaking on that show except that the acting was a cut above other shows. Roddenberry did go a few steps farther with Star Trek, adding a multi-racial crew and women having real authority as crew members or aliens.
Prior to Star Trek, the "alien" or "other" was a concept meant to inspire fear and justify violence. However it seemed that the series delighted in reversing this. Repeatedly the aliens are shown to be less dangerous than thought: the Talosians want the best for Capt. Pike, Balok isn't so bad, the Salt Creature is meant to be pitied, and so on. However if the villain was inanimate or a Frankenstein composed of man's ignorance, say NOMAD or the Planet Killer, then all violence the Federation can muster could be justified.
For my money Roddenberry, who appeared to be a casting couch throwback producer from an "Ed Wood" era, accomplished nothing so amazingly wonderful prior to Star Trek, and certainly nothing afterward that ever surpassed this singular achievement. He fought to keep Mr. Spock in the show and oversaw all the writing for a stable consistency,(I'm not a Harlan Ellison fan), so from this perspective, you could say he was born to create Star Trek then step off the stage. His whole life after Trek seemed warped by the show's gravity, and often he was pulled back into it for the 1987 follow on series and the first round of feature films.
Some audience members may prefer TNG, or the feature films. They may look back at the 1966 debut of Star Trek as merely "the future looked a lot like the Sixties". But why is it that the pure human emotions in those 79 episodes still attracts new converts? There must be something there that's communicating beyond the show's original five year mission. Star Trek still works as an adventure; one that considers human drama primary. That is unusual for any science fiction based story, wouldn't you say?
