As much as we love Star Trek, most of the greatness of the original will be found in the first two seasons. In Season 2, the show added a crewmember, Chekov, beefed up the Spock/Vulcan backstory, and produced one of the funniest and most loved episodes ever, "The Trouble with Tribbles." As we prepare for the new DVD release, here's our look at the best of the sophomore year.

"Amok Time"
When Spock experiences Pon farr, Kirk must take him to Vulcan to mate with his bride, T'Pring. Once there, T'Pring reveals that she would rather marry full-blooded Vulcan Stonn, and chooses Kirk as her champion to fight Spock to the death. This episode revealed many fascinating aspects of the relatively unknown Vulcan culture, aspects now engrained in the Trek mythos. The hour was also notable for its excellent detailing of the Spock/Kirk friendship, as it showed us just how much Kirk is willing to risk for his Vulcan friend ... and vice versa. The most rewarding moment has Spock actually cracking a smile upon learning that Kirk is alive.

"Mirror, Mirror"
Thanks to a transporter malfunction, Kirk, McCoy and Uhura end up in a brutal parallel universe. In introducing the popular "mirror" universe, this episode neatly turned Star Trek on its ear, revealing what the future might be like had humans not become so enlightened. The cutthroat tactics employed by various crewmembers are fascinating, as are Kirk's dealings with the goateed Mirror Spock, whose cold veneer masks a latent interest in working towards a more civilized universe. The framework established by this hour was so intriguing that the producers of Star Trek: Deep Space Nine mined it successfully throughout its seven-year run, setting several episodes in the Mirror Universe.

"Journey to Babel"
The Enterprise becomes a focal point for political intrigue when it is assigned to transport a group of ambassadors to a crucial diplomatic conference. This episode set up one of Trek's greatest familial conflicts by introducing us to Spock's parents — human mother Amanda and estranged father Sarek (the late great Mark Lenard), a Vulcan ambassador. Turns out Sarek didn't approve of his son's choice of career. Meanwhile, the political tension runs thick aboard ship, providing further dramatic conflict. But the heart of the episode is Spock's complex relationship with his father, a point that would be dealt with in future Treks, and the deep sense of logic ingrained within the Vulcan species. Leonard Nimoy and Lenard played off each other so perfectly that viewers immediately sensed a deep, flawed bond between the characters. A classic episode on many levels.

"The Trouble with Tribbles"
One of Trek's most amusing outings concerned itself with tribbles, those pesky little furballs that essentially do nothing more than reproduce at an incredibly rapid rate. And purr. This episode features one of the best crew run-ins with the Klingons, with some '60s-style fight action for Chekov and Scotty after a barrage of insults directed at their captain and ship. Of course, being the Original Series, the Klingons are up to no good, and the simple tribbles — who purr at everyone except Klingons — end up exposing the nefarious undercover agent Arne Darvin. A classic in the annals of creature comedy.

"Wolf in the Fold"
A spookier episode than the cheesy Halloween-themed "Catspaw," this tale of murder, malevolent spirits and mistaken identity is a classic whodunit. James Doohan's portrayal of the wronged Scotty is pitch perfect, as is John Fiedler's weasel-like Mr. Hengist. What makes this episode so great is that it leaves you guessing right until the very end. If Agatha Christie and Stephen King wrote a Star Trek script together, this might have been the result.

"A Piece of the Action"
Season 2 contains three purposefully funny episodes. One features tribbles, one robots ("I, Mudd") and this one which features an anachronistic Earth-like planet, Iotia, that was influenced by the book "Chicago Mobs of the Twenties" left behind many years ago by an earlier starship. The episode is light on its feet but provides some classic lines and images from Star Trek. Sure, the wardrobe department gets to dust off some cool threads, but it's the comic timing of William Shatner driving, or playing the improvised "fizzbin" card game, or chewing the scenery with his gangster schtick, that truly saves the day.

"The Ultimate Computer"
Yet another prescient metaphor for impending technology and blind faith in it (but predating any idea of software proliferation), this episode provides us with background on a famous personality, Dr. Richard Daystrom, the inventor of the duotronic computer system who is immortalized in the next century with the Daystrom Institute for science and technology. Great tension in this episode as we watch the total breakdown of a man whose lifelong work is rendered a failure, and whose identity is turned inside out.

"Assignment: Earth"
As a possible pilot spinoff, this "Assignment" was also a great Star Trek episode and concept. Gary Seven proves to be a memorable foil for Kirk and crew with his futuristic Bond-style gadgets, cool black cat and the unwitting assistance of Roberta Lincoln (played by rising star Teri Garr).

"Bread and Circuses"
Notable for getting in a brief, and oddly obtuse, reference to a planet's fledgling version of Christianity, "Circuses" is another "Gee-this-planet-looks-a-lot-like-a-period-in-Earth's-distant-past" episode. Of course, it involves members of a crashed Federation vessel on a developing planet that resembles ancient Rome. The catch is, what if the Romans had stayed in power all those years right up to the time of modern inventions such as cars and television? The idea of seeing gladiatorial fighting on prime time is something that we, fortunately, have yet to see. Then again, with reality TV gradually taking over, who knows?