Ranking the Episodes of the Original Series: A Comprehensive Guide

Among the show’s legendary characters, Spock, portrayed by Leonard Nimoy, stands out as the most iconic. The Vulcan first officer of the USS Enterprise, known for his pointy ears and stoic demeanor, has been a cultural icon since the series debuted and remains so today. In the sci-fi world, Spock’s significance to “Star Trek” parallels that of Darth Vader to “Star Wars.”

Although Spock was part of an ensemble cast rather than the central star, Leonard Nimoy’s portrayal ensured the character left a lasting mark. The show wisely acknowledged Spock’s popularity, centering several episodes around him. Here, we delve into five standout Spock episodes from “Star Trek: The Original Series.”

Spock’s abilities as a first officer are well-documented, but how does he perform as a captain? “The Galileo Seven” explores this, revealing that his reliance on logic isn’t always beneficial. The episode follows seven crew members of the USS Enterprise who crash on the hostile planet Taurus II. As the ranking officer, Spock must lead, a task complicated by the planet’s intimidating, primitive inhabitants.

We all know what Spock is like as a first officer, but how does he fare as a captain? “The Galileo Seven” answers this question, and it turns out that his cold logic isn’t always an asset. “The Galileo Seven” is about a group of seven USS Enterprise crew members who crash-land on the harsh planet Taurus II during a mission. As the highest-ranking officer on board, it falls on Spock to take charge. This is easier said than done when the group finds out that the planet is populated by big, hairy, caveman-like aliens who aren’t very happy to see them.

The fact that the only prominent characters in this group of seven are Spock, Leonard “Bones” McCoy (DeForest Kelley), and Montgomery “Scotty” Scott (James Doohan) should give you an idea that not everyone in the team survives the episode. Things aren’t helped by Spock’s rigid adherence to his logical approach at the expense of everything else. Yet, after some pushback from the others, he loosens up and gets the job done with an illogically risky Hail Mary plot that alerts the Enterprise to their location and saves the survivors. 

Rarely has a “Star Trek: The Original Series” episode offered so much insight into how a particular non-captain character acts in a leadership role during a high-stakes situation. As the show’s most prominent alien figure, the Vulcan is the perfect character for such an examination. 

“This Side of Paradise” is a sad-sack “Star Trek: The Original Series” episode that occasionally masquerades as a happy one. It takes us to Omicron Ceti III, where the USS Enterprise crew is investigating a peculiar situation. The planet’s colonists should be long dead of radiation poisoning, yet they seem to be thriving.

The source of the colonists’ health and happiness is a local flower that contains spores that heal and protect human beings. They also lock people in a constant state of bliss that allows them to live in a symbiotic relationship with the hosts. The problem becomes all the more interesting when the half-human Spock and several other crew members catch a dose of the spores. Immediately after being infected, the stone-faced Vulcan is smiling, having fun, and — most importantly — falling deeply in love with botanist and long-term Spock admirer Leila Kalomi (Jill Ireland).

This glimpse into what Spock might be like as a content human being is both illuminating and heartwrenching. After all, once he’s back to his usual stoic self, Spock doesn’t allow himself frivolities like love — and Leila, who actually loved him way before the spores, is so crushed that sheer heartbreak kills the spores in her own body. Despite this abrupt end, the experience leaves a mark on Spock: He states at the end of the episode that it was the first time in his life when he was truly happy.

“Journey to Babel” is a must-watch for two reasons: It’s a big Spock lore dump, and it introduces his parents. Vulcan ambassador Sarek (Mark Lenard) and Spock’s human mother, Amanda (Jane Wyatt), are notable characters in the “Star Trek” franchise, and as anyone who knows anything about Spock’s history is no doubt aware, his relationship with his father is not exactly the best. Sarek never liked his son’s decision to enlist in Starfleet, which has put a massive strain on their relationship to the point that Sarek initially refuses even to acknowledge his son.

“Journey to Babel” doesn’t take long to throw a wrench in this dynamic, though. As the Enterprise is hauling an array of diplomatic entourages to the planet Babel, Spock becomes central in an incredibly stressful situation when his father suffers a heart attack while also being suspected of killing a fellow diplomat. In the end, of course, all is well. Spock helps save Sarek’s life, another passenger turns out to be the assassin, and the Vulcan-human family has what to them passes for an affectionate heart-to-heart. 

The stealthily heartwarming conclusion explores the Vulcan concept of logical actions as a form of affection, which both Spock and Sarek are fully aware of, but Amanda only just now learns. The Vulcans are complex people, but after this episode, the viewer knows a little bit more of just what makes them tick — and how they display it.

“Amok Time” is one of the best episodes of “Star Trek: The Original Series,” and one of its most Spock-heavy to boot. It provides an interesting look into the surprising things Vulcans have to deal with, and serves as a magnificent window into the relationship between Spock and James T. Kirk (William Shatner). 

The Season 2 opener starts with Spock in a bad way. His uncharacteristic sullenness and disruptive behavior are symptoms of a recurring Vulcan mating season, pon farr, which must be obeyed or the Vulcan risks dying. The Enterprise sets course to planet Vulcan, where Spock’s assigned partner, T’Pring (Arlene Martel), proves to be less than willing to consummate their union. Instead, she has her sights on the full-blooded Vulcan Stonn (Lawrence Montaigne), and she’s hatched a clever plot to get rid of Spock. Her plan? To invoke a duel over the status of the relationship. The really clever part? T’Pring ensures that Stonn is safe from harm by choosing Kirk as her champion. Oh, and the fight is to the death.

The much-analyzed episode is laden with mental health subtext, and some viewers consider the moments between Spock and Kirk heavily queer-coded. Even stripped of all that, the kal-if-fee battle between Spock and Kirk and the ingenious way it’s settled are some of the finest moments of “The Original Series.” The way things ultimately play out is also very Vulcan, as Spock is ultimately appreciative of the logic behind T’Pring’s plot.

“Star Trek: The Original Series” Season 3 is the worst of the series, and it contains some of the most awful moments of the entire show. However, “All Our Yesterdays” — the penultimate episode of the series — is a late high note that ranks among the best “Star Trek” time travel episodes.

Here, “The Original Series” power trio of Kirk, Spock, and McCoy enter a time portal where the denizens have escaped the impending destruction of planet Sarpeidon. Kirk is stuck in a different time period than the other two, but they still remain in connection with each other, which gives the episode two distinct yet interconnected storylines to follow. As McCoy and Spock encounter a lonely survivor called Zarabeth (Mariette Hartley), Spock steps front and center. He soon starts to develop an emotional connection with Zarabeth, but thanks to the distant past period they’re trapped in, he also starts regressing into the emotional and primitive savagery of ancient Vulcans.

Like many of the best Spock episodes, “All Our Yesterdays” plays with the pros and cons of the character’s usual stoicism while forcing him to overcome an impossible situation; In this case, the need to navigate his feelings for Zarabeth (who can’t return to the present) while still ascertaining the safety of McCoy (who can only return if Spock accompanies him). The episode distills it all into one powerful Spock storyline and makes the most of every single second the character is onscreen.