The Citizen Kane of the Star Trek universe, this deeply personal episode is almost universally accepted as the greatest of the Original Series and is often cited as the best installment of any Star Trek series. It's a reputation that's well earned.
Like the fifth Star Trek feature film, the roots of the episode lie in a story that is compelling in its own right but has budget issues and doesn't quite fit into Star Trek. For "City on the Edge", however, several of the show's best "in house" writers, including Roddenberry, Coon, and Fontana, all took turns banging the teleplay into shape, dispelling the notion (along with TNG's "Yesterday's Enterprise") that too many cooks spoil the broth. (They even work in a scene that parallels their battles with the original writer, with Spock, like Ellison, coming up with expensive items he thinks could help, and Kirk, like the show's producers, trying to explain the concept of budget. "Mr. Spock, this bag does not contain platinum, silver, or gold, nor is it likely to in the near future").
In the end, the part of the episode that suffers the most from cost and time saving measures is the beginning. A time traveling device known as the Guardian of Forever, originally meant to be part of a much more complex society, is reduced to a "magic gateway" the like of which is seen more often in juvenile fantasy. Coming out of left field, it seems contrived (which, of course, it is) and a bit superfluous. While it might be sacrilegious (and is certainly useless) to suggest improvements in the teleplay, it probably would be better if the Guardian was mute, taking away some of its "great and powerful" Oz like silliness and giving it more of a surreal feel shrouded in mystery. Mr. Spock could figure out what the entity is without help, and he and the Captain, after McCoy has entered, could deduce that the doctor has changed history and erased their present, thanks to a new "history" shown by the Guardian and a lack of communication with the Enterprise. (It might even be fun to see Kirk an company figure it all out for themselves).
But the Guardian is only a means into the story. And with its beautiful design (thanks to Desilu's Roland Brooks, filling in for Star Trek designer Matt Jeffries, who had the flu) and a voice supplied by Bart LaRue (previously the voice of Trelane's father), it does the job, getting the "big three" to the streets of 1930s New York (a redress of the streets of Star Trek's sister show, The Andy Griffith Show).
Seeing the Enterprise crew in the 20th Century is always a treat, with the fun of seeing them wearing period clothing, rubbing shoulders with the regular folk, and dealing with the local authority figures never getting old. Here, the core of the episode features Kirk and Spock, with Shatner and Nimoy having worked together just long enough to have their chemistry fine tuned. McCoy comes along in time (pardon the pun), but more important is a character the like of which few of Star Trek's time travel stories have had: a character from the past who is not only as kind, intelligent and forward thinking as our beloved Enterprise heroes, but in some ways surpasses them. Playing 20th Century social worker Edith Keeler, Joan Collins's first appearance in the episode instantly gives the story an added spark, elevating the drama and the performances of the regulars, making every scene that follows must see TV. It's uncanny to see how Keeler handles Kirk and Spock, with this 1930s woman so easily putting both men in their places. Her comments about Spock belonging at Kirk's side, "as if you've always been there and always will" reverberated throughout the 1970s and 1980s as Star Trek played in an endless loop of syndication and the feature films began coming out, turning Keeler into more of a visionary than the writer intended when the line was written in 1967.
Meanwhile, William Shatner, who is always at his best when he's force to play up to the level of a woman rather than down to one, gets a rare chance to do just such. Normally, Kirk's way of handling a lady is to get a silly grin on his face, tell a few white lies, and try to get in her pants. But when Keeler catches him in a lie the instant they meet, his attitude suddenly changes. He tells the truth, he allows himself to be vulnerable, and he treats her with respect. As the scenes progress (including a night stroll where they walk by Floyd's Barbershop, familiar to any fan of Mayberry) we really do believe Kirk might be falling in love, setting up the focal point of the episode's drama: he can't have his cake and Edith too. It's all tied together by arguably Star Trek's finest combination of new and old music, with nostalgic cues from the past (most notably the romantic music from "Conscience of the King") mixed with new cues by Fred Steiner, including 1930s style music that blends with the 1931 song, "Goodnight, Sweetheart".
The period touches enhance the feeling of Kirk, Spock, and McCoy being fish out of water, but with the Keeler issue none finds himself in a more unique situation than the captain. There is no opportunity to outwit a computer. No chance to do an end run around an authority figure. No battles with aliens. It's the Kobayashi Maru fifteen years before Star Trek II.
Of course, if this type of episode had come along later in Star Trek's life, it likely would have been a two parter to allow it to dig deeper into the story and spread the out expense (which, at $245,000, was well above the normal $190,000). In fact, with the story seemingly only getting richer going into the last act, a first time viewer might expect to see "to be continued" as the ending approaches, only to be blindsided by the sudden climax; making it all the more dramatic.
But the truth is that "City", directed by prolific television and film director Joe Pevney (who gives the episode a cinematic quality) brings together so many unique elements in an alchemy of near perfection, the episode essentially divides the original series in two: there's this episode and there's the other 78.
Sadly, Keeler never appears in Star Trek again, despite the seventh Star Trek movie having the perfect spot for her. (They instead use the engimatic "Antonia" as Kirk's lost love). The Guardian, however, does return for the best Animated Series episode, "Yesteryear", where Spock goes back in time to help his younger self.
Remastered: As Star Trek's signature episode, you can bet that CBS Digital was pouring over this one looking for anything they could improve. The truth, however, is that the episode is nearly as flawless technically as it is artistically. Taking place mostly in the past, there are few shots of the ship in orbit, and yet even these are rather good to begin with. CBS Digital replaces them, of course, with upgraded shots and fixes a "Twilight Zone ish" panning shot of Kirk looking up into the stars, originally a complicated bit of compositing that didn't come off quite right. (In the original, the live set bleeds into the Beyond these, there aren't any noticeable changes, at least for non eagle eyed viewers. They do re-matte in the newspaper clippings Spock looks at on his tricorder (enlarging them slightly in the process) so there are no black matte lines on the device's screen; the lines, however, always looked like part of the tricorder anyway and were never a real problem. CBS also redoes static lines Spock keeps getting in his equipment, changing the last bit of static (when the circuits burn out) to a more colorful effect. (I only wish I could have taken the money they spent on these effects and moved it into "Errand of Mercy" for a needed matte The moment where a stranger accidently eliminates himself with McCoy's phaser has also been subtly tweaked to improve the effect.
But the best work in the episode might be the end: as the crew beams out, the scene lingers on a shot of the Guardian to allow some credits to appear. The problem for the original team is that the Guardian has some fog around it, and having something moving for a beam out shot and a credit sequence was tricky for them in 1967. As such, in the original, the fog periodically freezes. Fortunately, CBS Digital is all over it like Scotty at an all you can eat buffet. The new version features perfectly rolling fog all the way to the fade to black.