Why is Star Trek IV named The Undiscovered Country? It’s a pretty cool sounding name. It’s definitely more provocative than The Wrath of Khan or The Search for Spock. Star Trek movie subtitles are hit and miss. The Motion Picture was intended to let audiences know that it was a high budget film, similar to Superman The Movie. Looking back, it’s unnecessary because the average movie-goer can probably tell that Superman The Movie or Star Trek The Motion Picture are in fact movies instead of television shows, but considering their enormous budgets, it’s understandable that the studios didn’t want to leave anything to chance.
For Star Trek II The Wrath of Khan, it’s understandable that the studio would back a sensational sounding name after the bland taste The Motion Picture left with audiences. The Search for Spock is a straight to the point subtitle and gets the job done. The Voyage Home is where they get a bit more abstract, but I think it works great. The Final Frontier is basically a cool sounding Star Trek catchphrase that they were probably waiting to use and finally did.
As you probably already know, The undiscovered country phrase was lifted out of Hamlet:
To grunt and sweat under a weary life,
But that the dread of something after death,
The undiscovered country from whose bourn
No traveler returns, puzzles the will
And makes us rather bear those ills we have
(Act 3, Scene 1)
So, The Undiscovered County refers to an after-life. Director Nicholas Meyer is a huge Shakespeare buff, as evident from the numerous quotes and references dropped throughout the movie. He initially want this subtitle used for Star Trek II. Within the context of that film, “The undiscovered country” would refer to Spock’s death. It kinda, sorta, not-really works. Spock dies at the end of the film, so the movie itself doesn’t really dwell on death and/or mortality. The film brushes over notions of aging, redemption and revenge, but those are distinctly different thematic notions than death.
In any case, that brings us to Star Trek VI. Chancellor Gorkon toasts to “the undiscovered country” during the dinner scene. In that context, the phrase seemingly refers to a vague socio-political period following the end of the Klingon-Federation cold war. It would be a stretch to apply that scenario to the notion of death. The cold war would be the thing that dies and the undiscovered country would be the period afterwards. Again, it’s a bit clunky but the phrase “the undiscovered country” conveys the general idea.
I’ve never been satisfied with that though. Then I realized that Star Trek VI itself was a self-aware finale to the original series crew movies. Going into production, it was widely acknowledged as being the final Shatner/Nimoy Star Trek film. This is where “the undiscovered country” really fits the context. The original series is ending with character arcs completing. Kirk finally truly accepts his age and is ready to move on (as long as you don’t count Generations). Spock achieves the balance between his Vulcan and his Human sides. For examply, he speaks of faith in response to Valeris’ logic and overall, the Federation-Klingon conflict which has been an element in the franchise since the mid-1960s is finally ending. Kirk, Spock and Star Trek itself aren’t dying, but they are entering the next phase of their existence that audiences won’t be a part of (unless you count “Unificiation,” Generations and the Abrams Star Trek movies). The movie leaves us with the sense that the adventures of the crew of the starship Enterprise are ending. “The undiscovered country” implies the period of their existence following the end of their voyages together.
TL/DR: “The Undiscovered Country” is a Shakespeare Hamlet reference describing a notion of an after-life. Within the context of Star Trek VI, it refers to the end of not only the Federation-Klingon cold war, but the end of the voyages of TOS crew movies.