One of the most famous characters from the original Star Trek television series is the half-Vulcan Mr. Spock, played by Leonard Nimoy. Spock has a first name which is never stated in the series, but is apparently unpronounceable by humans.
Spock was the son of the Vulcan ambassador Sarek and his human wife Amanda. Although Spock identified himself as Vulcan -- the first Vulcan to join Starfleet, much against his father's wishes, he had an ongoing internal conflict between the reason and logic of his Vulcan half and the emotion and intuition of his human half. By human standards, however, he was incredibly logical.
On the USS Enterprise, he was Science Officer under Christopher Pike (in The Cage), and later First Officer and Science Officer under James T. Kirk.
Spock had an older half-brother, Sybok, who eschewed pure logic, resembling the relationship between Data and Lore.
The Enterprise itself was saved solely by Spock's courage and self-sacrifice in Star Trek II: The Wrath of Khan. Entering the anti-matter chamber with no protection he allowed for the warp engines to be brought online just in time to allow the Enterprise to escape the brilliant explosion that would create the planet Genesis. He died from exposure to the radiation.
In an honorary "burial" Spock's body was enclosed in a torpedo and fired onto the rapidly forming Genesis planet. Thanks to the unique environment of the planet (the work of the Genesis Project) his body was actually "re-birthed" on the planet and he is rediscovered in Star Trek III: The Search for Spock.
In the early 2370s, Spock was seen outside his then-role as Federation ambassador on the Romulan homeworld of Romulus. He was attempting to bring about a peace between the Romulans and Vulcans, healing a rift between the two peoples thousands of years old. (Vulcans and Romulans are the same species; Romulans left the planet Vulcan after refusing to accept Surak's logical philosophy.) The events of the tenth Star Trek movie hint that his mission was a failure, and while no canon sources discuss Spock's "current" whereabouts, it is a reasonable supposition that he is dead.
See also: Slash fiction