Yes, it's taken me this long to write this.
After the original pilot of Star Trek was shown to the network executives, Roddenberry was given an ultimatum. "Lose the woman or lose the alien."
He "Kept the alien and married the woman." (The original first officer, Number One, was played by Majel Barrett Roddenberry).
And in doing so he combined the two characters, giving the half-human, half-Vulcan Spock Number One's job...and her computer-like personality.
Which led to the creation of the Vulcans, and the creation of one of the most memorable alien characters in the history of science fiction.
The actor he chose to play the alien was a thirty-four year old unknown, a Ukrainian Jew who had previously only played bit parts, many of them uncredited.
This was Leonard Simon Nimoy, and Spock was the part that made him a household name. He invented the idea of the Vulcan nerve pinch and the familiar Live Long And Prosper salute - based off of kabalistic principles.
He was known as Spock, but he was many other things as well.
His other acting credits included Dr. William Bell in Fringe, General Konrad in Invasion America, Paris in the Mission Impossible TV show, John Walking Fox in Gunsmoke. Like just about everyone else he was in a Man From U.N.C.L.E. episode, The Project Strigas Affair, along with...William Shatner. (Yes, they were both in the same episode).
He was a highly talented voice actor who did a lot of video game work and a fair bit of work for the Transformers franchise. And he was a poet, a singer/songwriter, a science show host, a stage actor (He did a run as Sherlock Holmes), a talented director, a skilled photographer and a pilot.
Oh, and he loved his fans. There wasn't much this man couldn't do, but to most of us, he will always be Spock. Including at some level to himself - his second autobiography was titled "I Am Spock."