The first Star Trek is a “space Western.” A few centuries in the future, humanity and other sentient races have established colonies beyond their home worlds but the galaxy is still largely untamed, mysterious, and dangerous. Captain Kirk leads the crew of the starship Enterprise (mostly human, but with the half-Vulcan Spock as second in command) as they explore “the final frontier” of outer space: expanding scientific understanding, making first contact with alien races, and dealing with various threats along the way.

As the beginning of all things Star Trek, the series takes a while to define its identity and find its stride. Be prepared for some inconsistent tone, themes, and terminology early on - the Federation doesn’t even get mentioned until two-thirds of the way through the first season. But the things that make Star Trek what it is are clearly present and there are plenty of franchise-defining episodes from the very beginning. By the second season there’s even a bit of worldbuilding and both reference to and return of some familiar faces. The third and final season was unfortunately beset by budget and production problems resulting in very uneven quality, but there are still some enjoyable and memorable episodes worth your time.

Episodic or serial?

Episodic. There are some running themes but no real story or character arcs and very few recurring characters outside of the core cast. There is only one two-part episode.

Idealistic or cynical?

Idealistic, mostly. There are a few episodes that take darker turns but this is a show where sticking to your principles pays off and good defeats evil.

Worth watching?

Yeah, at least the highlights.

This is the first Trek. It took some time to find its identity and not all of it has aged well, but it lays the foundation for everything that comes later and has made the biggest impression. It’s worth having a sense of who Kirk and Spock are, both to understand Star Trek the cultural phenomenon and to understand the callbacks that come in later series.

I recommend watching a few four- or five-star episodes and then deciding how deep you want to go with it. If you aren’t enjoying it, move on. If you decide you want to spend more time with this crew you can come back at any time and watch episodes you skipped previously - because the series is so episodic, there’s no real problem going out of order.

In fact, episodes were aired in a different order from which they were produced. This can make the first handful of episodes disorienting as some details like the design of the uniforms take a while to get nailed down. If you watch in original airdate order, be prepared for these things to bounce around a bit.

Anything else that should be watched first?

Nope! This is the very first Trek. There are technically a couple of prequel series that take place chronologically earlier, but they were created decades later and generally assume you have familiarity with The Original Series.

What should be watched after this?

If you want more of this crew, a couple of episodes of The Animated Series are worth watching if you happen to have easy access to it. There are also six feature films, several of which are worth watching.

Then you should head on to The Next Generation.