I am the seemingly rare breed of geek that loves both Star Wars and Star Trek. They are such different breeds of science fiction, I think there is room for both. I actually discovered Star Trek first, being introduced very young by my dad to the original live action tv show. The first movies came out when I was a kid. I used to read the novels. It wasn't until I was a teenager that I discovered that there was another Star Trek show, though, continuing the five year mission. Also known as Star Trek, later amended to Star Trek The Animated Series to differentiate it from the live action show, It helped keep the franchise alive between the original show and the Motion Picture.
The show came out in 1973. Most of the original cast came back. Walter Koenig was not included, but he did write an episode. Instead of Chekov, there were two aliens on the bridge with Sulu. (Sulu and Uhura were only included at the insistence of Leonard Nimoy.) Even a few guest stars were voiced by the original actors from the live acion series, like Sarek and Harry Mudd.
One of the great things about the show is since it was animated, they could afford to have aliens who didn't look like humans in cheap costumes, or puppets. They could have settings that looked really alien. They were still confined by budget, but nearly as much as the live action show. They got to stretch their imaginations a bit.
The show was geared not just for the mostly adult fan base of the first show, but for families and kids as well. As a result, the plots could be a little silly at times, but I would argue they never got as silly as some of the episodes of the third and last season of the Original Series. Abraham Lincoln makes nary an appearance. The animation was mostly pretty good, though there were mistakes. The voice acting is decent for the time. There are times when the dialog seems a little off, but overall it's still pretty watchable.
Though it was later removed from canon, the show introduced a couple of important Trek elements. It explored Spock's difficult childhood, and his struggle to reconcile his Vulcan heritage and the part of him that is so very human. It also established Kirk's middle name as Tiberius. It was the first time that we saw aliens serving on the bridge crew, significant for a show about equality and inclusion. There was an episode that showed the Enterprise had a holodeck, though it is called the Rec Room. This is way before the Next Generation. Another significant moment, Uruha takes command of the Enterprise. The only other time a woman is shown in command of the ship was during the original pilot, later recycled into the two part episode The Cage. The Animated Series also garnered Star Trek it's very first Emmy win.
One of the hallmarks of the original show is how it dealt with major philosophical and social questions of the day. Fear of the other is a recurring theme in those old shows, whether it be the first time they meet the Romulans, causing distrust of Spock, or the famous episode with the guys whose faces are half white and half black. The Animated series focused more on adventure and less on important messages. This was a loss for the show, but understandable as they felt they were making a cartoon for kids. This was an era when it was not understood widely that animation could be enjoyed and appreciated by adults.
I enjoy the show for what it is, but I can only imagine what it must have meant to Trek fans in 1973. There was not yet the immense library of Trek novels that we have today, there were no other shows or movies. This show was the first sign they had that Trek would continue on and not die with the Original Series. It must have been a huge source of excitement that Trek was coming back, even if it was as a cartoon. It helped keep the Trek flame alive until the movie franchise could secure it's place in pop culture. And it is enjoyable to watch in it's own right.
Here is a clip from an episode. Enjoy.