If you have no time to watch all 79 Star Trek episodes from the original series, there are a dozen essential espisodes that are must-see TV.

These “Trek TOS Twelve” episodes (listed alphabetically with their original broadcast dates on NBC-TV and episode number) will give you a representative perspective of the persuasive powers embedded in Star Trek characters and storytelling from the original series.

“Amok Time” (September 15, 1967, episode #34)

The usually cool, collected Mr. Spock freaks out when overtaken by an overwhelming mating urge. The only cure is to return to the Vulcan home planet so Spock can participate in the Kunat kalifee, the Vulcan marriage ritual that pits Kirk against Spock in a fight to the death. In one of the most quotable lines from Star Trek, Spock succinctly and poetically sums up the power of the urge to mate and sexually interact this way: “The wanting is more than the having.”

“The City on the Edge of Forever” (April 6, 1967, episode #28)

While investigating a time displacement phenomenon in orbit of a desolate planet, Dr. McCoy accidently injects himself with a toxic drug that makes him hysterical and paranoid. He beams down to the planet and Kirk and Spock follow in search of the doctor. They find a time vortex that proves to be the source of the time displacement. McCoy escapes through the vortex and in doing so, changes history for the Enterprise crew. Spock and Kirk must go back in time through the vortex to attempt to set right what McCoy changed.

“The Corbomite Maneuver” (November 10, 1966, episode #3)

The Enterprise narrowly avoids disaster when it meets a strange spacecraft. Kirk takes every evasive action to avoid a collision with the alien craft and is finally forced to blast it with a phaser beam. By use of bluffing, the Enterprise breaks away leaving the alien ship dark and apparently helpless. When the damaged ship sends out a distress signal, Kirk orders a rescue and discovers the sole occupant of the ship has also been bluffing.

“The Devil in the Dark” (March 9, 1967, episode #26)

Kirk and Spock respond to a distress call from a mining colony where there have been more than 50 fatalities. The culprit is a huge silicon-based creature that can move through solid rock. Spock uses the Vulcan mind-meld to telepathically communicate with the creature that calls herself a Horta. She justifies the killing of the miners because they have been destroying her silicon eggs. The Horta explains that she was acting solely in the defense of her offspring.

“The Enemy Within” (October 6, 1966, episode #5)

Kirk, Sulu and four other Enterprise crewmen are beamed down to the surface of a planet. When Kirk beams up to the ship, he becomes his own worst enemy, literally and physically. A transporter malfunction splits Kirk into two men–one who is hostile with an animalistic bearing, and the other who is peacefully docile but indecisive.

“For the World is Hollow and I Have Touched the Sky” (November 8, 1968, episode #65)

Dr. McCoy, who discovers that he has an incurable, fatal disease, agrees to live out his final days inside a created world inside an asteroid. Don’t worry, he is cured at the end of the episode. McCoy falls in love with a queen, Natira, who chooses McCoy as her mate. The inhabitants do not know they live inside an asteroid that will soon be destroyed when it collides with the Enterprise. Kirk has no choice but to reveal the actual nature of the created world to Natira. She is stunned to realize that her society’s religious leaders had been lying about the world inside the asteroid. She provides another essential quotable Star Trek line when she asks a profound question about the credibility of her religious faith: “Is truth not truth for all?”

“Journey to Babel” (November 17, 1967, episode #44)

The Enterprise is bringing important delegates to a United Federation of Planets meeting. An assassin who is discovered posing as one of the delegates nearly kills Kirk, so Spock must assume command of the Enterprise. Vulcan ambassador Sarek, who is Spock’s father, is on board with his wife, Amanda, from planet Earth. Sarek suffers a nearly-fatal heart ailment and requires an immediate blood transfusion. The only one aboard the Enterprise who can be a blood donor to save Sarek is his son, who refuses because of command responsibilities.

“Mirror, Mirror” (October 6, 1967, episode #39)

Kirk, McCoy, Scotty, and Uhura are unwittingly beamed to a very different startship Enterprise in a parallel universe. They discover that the transporter has malfunctioned (once again!) forcing them literally to fight for survival aboard that other Enterprise in a most violent and savage universe.

“Shore Leave” (December 29, 1966, episode #17)

The Enterprise crew seeks a much-need shore leave on a beautiful Earth-like planet. Advanced technology on the planet quickly fulfills each person’s secret desires, some of which have unintended consequences. McCoy gets killed by a medieval black knight. Don’t worry, he is resurrected at the end of the episode. Kirk enjoys violent confrontations with an old enemy from his youth and then rediscovers forgotten sexual pleasures with a former girlfriend. The secret to survival on this amusement park planet is to be careful what you wish for.

“This Side of Paradise” (March 2, 1967, episode #25)

Kirk, Spock, McCoy, and Sulu beam down to a planet, expecting to find that radiation has wiped out an agricultural colony there. Instead, they discover a quite healthy group of colonists thanks to parasitic spores that have entered everyone’s bodies providing them with extreme tranquility and perfect health. The landing party is similarly infected. Under the influence of the spores, Spock falls in love with a young female colonist who is a former acquaintance. Kirk discovers that he can reverse the effects of the spores in himself with violent aggression. He tests this antidote on Spock by angering him, and the cure works. Together, they insite a riot, which reverses the effects of the spores, thus freeing the crew and the colonists by using violence as the cure for paradise.

“The Trouble with Tribbles” (December 29, 1967, episode #42)

Kirk and his crew are unhappy about the indignity of their mission to transport a rare wheat germ named quadrotriticale from Deep Space Station K7 to a nearby planet as part of their rivalry with the Klingon race. At the deep space station, the Enterprise crew must deal with small, furry alient creatures called Tribbles. They consume quadrotriticale quickly. They also reproduce extraordinarly quickly, which creates a humorous tone to the story. When Tribbles are found dead in the cargo hold after consuming quadrotriticale, Kirk discovers that the grain inteaded for planetary distribution has been poisoned by a Klingon saboteur.

“Turnabout Intruder” (June 3, 1969, episode #79)

The very last episode of the original series is the tale of an attractive, but scorned woman, Dr. Janice Lester, who uses advanced technology to exchange bodies with Kirk. This out-of-body experience traps the mind and consciousness of the womanizer Kirk in the body of a beautiful woman–an ironic fate, indeed. Dr. Janis Lester, who resents the male-dominated world of the 23rd century, is mad with power when she finds that her mind and consciousness is inside the body of Captain James Tiberious Kirk. William Shatner’s skills and talents as he portrays a man with a woman’s mind and consciousness inside are sheer delight to watch, but he will have to wait 35 years before receiving his first Emmy award for acting.