THE MAN TRAP
The Enterprise is ravaged by a creature that sucks the salt from its victims' bodies, and that is capable of assuming any identity.

CHARLIE X
A teenager, raised by aliens and possessing some of their unusual powers, proves incapable of adjusting to human society and emotions.

WHERE NO MAN HAS GONE BEFORE
In passing through an energy barrier at the edge of the galaxy, some Enterprise crew members find their ESP powers enormously heightened. [Note: although this was the third episode aired, it was actually filmed before the others and was the 2nd pilot made for the show. The first, "The Cage" was later made into the two-part episode, "The Menagerie"]

THE NAKED TIME
A strange malady strikes the crew of the Enterprise, causing them to succumb to their innermost desires.

THE ENEMY WITHIN
A transporter malfunction splits Kirk into two personalities, one brutal and incapable of control, the other gentle and incapable of command.

MUDD'S WOMEN
Jack-of-all-illegal-trades Harry Mudd is transported aboard the Enterprise along with his cargo, three irresistibly beautiful women.

WHAT ARE LITTLE GIRLS MADE OF?
Nurse Chapel's long-lost fiance turns up in control of a mechanism capable of producing android replicas of live beings.

MIRI
The landing party contracts a disease that strikes after puberty, while the children still alive on the planet refuse to let them contact the ship for help.

DAGGER OF THE MIND
A deranged escapee from a penal planet causes Kirk to investigate the psychiatric treatments being administered there.

THE CORBOMITE MANEUVER
To stave off an attack by an alien vessel, Kirk concocts the now-famous "Corbomite" bluff.

THE MENAGERIE parts 1 and 2
Spock risks the death penalty by hijacking his old commander, Captain Pike, to Talos IV. Court-martial testimony (actually scenes taken from "The Cage", Star Trek's original pilot episode) recreates the story of Pike's earlier encounter with the Talosians.

THE CONSCIENCE OF THE KING
The star of a Shakespearean acting company may be the infamous "Kodos the Executioner".

BALANCE OF TERROR
Kirk matches wits against a Romulan commander in the first encounter between the species to occur in several decades.

SHORE LEAVE
The crew of the Enterprise takes shore leave on a planet where their every thought is immediately converted to reality.

GALILEO SEVEN
Spock finds himself in command of the shuttlecraft Galileo, stranded on a hostile planetoid.

THE SQUIRE OF GOTHOS
The crew of the Enterprise are made unwilling guests of the powerful but capricious General Trelane (retired).

ARENA
Kirk and a reptilian alien must duel to the death to determine whose ship will survive.

TOMORROW IS YESTERDAY
The Enterprise is accidentally flung back to the year 1967, where they find they must take desperate measures in an attempt to avoid changing history.

COURT-MARTIAL
Kirk is placed on trial when the ship's record tapes show he committed an error that cost a man's life.

RETURN OF THE ARCHONS
An entire planet is under the total mental control of a mysterious being known as "Landru".

SPACE SEED
The Enterprise runs across a "sleeper ship" full of supermen fleeing their defeat in the Eugenics Wars.

A TASTE OF ARMAGEDDON
The Enterprise and its crew are declared casualties in an interplanetary war entirely simulated by computers.

THIS SIDE OF PARADISE
Strange spores cause the entire crew of the Enterprise to mutiny and beam down to a planet where all work is done in unity and contentment.

THE DEVIL IN THE DARK
A mining operation is ravaged by a monster that dissolves men's bodies.

ERRAND OF MERCY
Kirk and Spock, stranded on Organia, attempt to interfere with the Klingon occupation of the planet, despite the Organians' insistence upon the non-necessity of violence.

THE ALTERNATIVE FACTOR
A schizophrenic personality named Lazarus seems to be the key to an anomaly in the space-time fabric of the universe.

THE CITY ON THE EDGE OF FOREVER
McCoy, suffering from an overdose of cordrazine, vanishes through a time portal and somehow changes the past. Kirk and Spock follow in an effort to rectify whatever it is that McCoy has done.

OPERATION--ANNIHILATE
The Enterprise faces an onslaught by parasitic creatures that invade the nervous system to take control of their hosts.

AMOK TIME
Spock is forced by the instinctive Vulcan mating cycle to return to his home planet and take a wife.

WHO MOURNS FOR ADONAIS
The Enterprise is seized by a being claiming to be the god Apollo, who requires their worship to survive.

THE CHANGELING
Nomad, an ancient Earth probe, has combined with an alien probe to form an incredibly powerful mechanism that is determined to destroy all "imperfect" life forms.

MIRROR, MIRROR
Kirk, McCoy, Scott, and Uhura are accidentally exchanged with their counterparts in a parallel universe, where instead of the Federation they find a violent, dictatorial Empire.

THE APPLE
The Enterprise finds itself under attack by Vaal, a machine that guides the actions and even the environment of a primitive populace.

THE DOOMSDAY MACHINE
The starships Enterprise and Constellation battle an enormous machine that destroys planets and consumes them for fuel.

CATSPAW
Amidst an atmosphere of witches and dungeons, a pair of aliens use seemingly magical powers in an attempt to trick further scientific information from the people of the Enterprise.

I, MUDD
The Enterprise is forced to a planet populated by androids and ruled by their old nemesis, Harcourt Fenton Mudd.

METAMORPHOSIS
A shuttlecraft is forced down to a planet as company for a stranded spaceman, who has been kept young by a gaseous alien called the "Companion".

JOURNEY TO BABEL
Crisis piles atop crisis when the Enterprise is in charge of transporting a volatile cargo of Federation diplomats, including Spock's parents.

THE DEADLY YEARS
Kirk is relieved of command when he and other officers contract a disease that results in senility and death by old age within days.

OBSESSIONS
Kirk disregards all other responsibilities in an effort to destroy a gaseous cloud that absorbs red corpuscles from human bodies.

WOLF IN THE FOLD
Scotty appears to be the only logical suspect in a bizarre series of murders.

THE TROUBLE WITH TRIBBLES
Kirk must put up with Federation bureaucrats and hordes of hungry tribbles while protecting a shipment of quadrotriticale (wheat) against Klingon sabotage.

THE GAMESTERS OF TRISKELION
Kirk, Uhura, and Chekov are captured for use in gambling conflicts.

A PIECE OF THE ACTION
Kirk must figure out a way to counteract the effects of an earlier expedition, which caused a planet's civilization to pattern itself after the Chicago mobs of the Twenties.

THE IMMUNITY SYNDROME
A gigantic single-celled creature, which feeds on the energy necessary to our form of life, invades our galaxy.

A PRIVATE LITTLE WAR
When the Klingons hasten the arms development of one faction on a hitherto peaceful planet, Kirk must arm the other side in order to maintain a balance of power.

RETURN TO TOMORROW
Highly advanced alien minds "borrow" bodies, including those of Kirk and Spock, in order to build permanent android bodies. One of them, however, does not wish to leave his borrowed body.

PATTERNS OF FORCE
A Federation historian ignores the Prime Directive and reshapes a planet's society along the lines of Nazi Germany.

BY ANY OTHER NAME
A group of aliens from the Andromeda galaxy commandeer the Enterprise to make the journey back home.

THE OMEGA GLORY
Captain Tracy, believing he has found a planet containing the secret of eternal youth, interferes in the struggle between the two planetary cultures, the Yangs and the Kohms.

THE ULTIMATE COMPUTER
The Enterprise is put under total control of a new type of computer, which then refuses to relinquish control.

BREAD AND CIRCUSES
1968 The Enterprise encounters a civilization that combines the features of the Roman Empire with 20th-century technology.

FRIDAY'S CHILD
Negotiations over mining rights become a battle for survival when McCoy unintentionally violates a tribal taboo.

ASSIGNMENT: EARTH
On a historical fact-finding mission to 1969, the Enterprise accidentally intercepts an interplanetary agent out to sabotage an orbiting nuclear platform.

SPOCK'S BRAIN
A mysterious woman surgically removes Spock's brain.

THE ENTERPRISE INCIDENT
Kirk goes mad and Spock turns traitor in an attempt to steal an improved cloaking device from the Romulans.

THE PARADISE SYNDROME
In a state of amnesia, Kirk marries and finds happiness with Miramanee, an Indian maiden. Meanwhile, Spock must find a way to save her planet from an impending meteor collision.

AND THE CHILDREN SHALL LEAD
A group of children, under alien domination, play on the crew members' secret fears in order to gain control of the ship.

IS THERE IN TRUTH NO BEAUTY?
Miranda, a telepath, is jealous of Spock's greater abilities in forming a mind-link with Kollos, an alien so ugly that the very sight of him can drive a man insane.

SPECTRE OF THE GUN
Kirk et al. find themselves on the losing side of the gunfight at the OK Corral.

DAY OF THE DOVE
Klingons and the Enterprise crew must unite to overcome an alien who feeds on the hatred between them.

FOR THE WORLD IS HOLLOW, AND I HAVE TOUCHED THE SKY
McCoy, suffering from a fatal disease, finds himself romantically entangled with the priestess governing a planetoid/spaceship on a collision course with another planet.

THE THOLIAN WEB
1968 The Tholians entrap the Enterprise, not believing that the crew is merely trying to save Kirk from a hyperspace warp.

PLATO'S STEPCHILDREN
The dwarf Alexander's lack of mind-over-matter abilities may be the only clue to aid Kirk in defeating a band of telekinetics.

WINK OF AN EYE
The Enterprise is invaded by beings who move too fast for human eyes to detect.

THE EMPATH
Kirk, Spock, and McCoy are manipulated by aliens who use them to teach compassion to a girl capable of absorbing the pain and injuries of others.

ELAAN OF TROYIUS
The Enterprise's task of transporting an imperious woman to another planet for marriage is complicated by Kirk's falling in love with her.

WHOM GODS DESTROY
Captain Garth, having taken over the penal planet where he was being treated, uses his ability to change shape in an attempt to get aboard the Enterprise.

LET THAT BE YOUR LAST BATTLEFIELD
Two two-toned beings try to get Kirk to take sides in their racial disputes.

THE MARK OF GIDEON
Kirk is decoyed into a replica of the Enterprise. While Spock searches for him through a maze of diplomatic red tape, the people of Gideon are using him as a source of alien infection.

THAT WHICH SURVIVES
A mysterious woman whose touch is death threatens the landing party.

THE LIGHTS OF ZETAR
An electrical cloud formed by the life-essences of the long-dead Zetarians seeks to possess the body of Scotty's new-found sweetheart.

REQUIEM FOR METHUSELAH
Flint, an immortal, uses Kirk to rouse emotions in an android, so that she will become fully human and can be a suitable, immortal mate.

THE WAY TO EDEN
A group of space hippies are searching for the legendary planet of Eden.

THE CLOUD MINDERS
Kirk's attempt to pick up a shipment of a vital mineral embroils him in the demands of the oppressed miners against the rulers.

THE SAVAGE CURTAIN
Lincoln of Earth and Surak of Vulcan join Kirk and Spock in battle against a group of villains, while alien observers examine the distinctions between good and evil.

ALL OUR YESTERDAYS
A rescue mission to a planet whose sun is about to nova results in Kirk, Spock, and McCoy being sent to various eras in the planet's past.

TURNABOUT INTRUDER
A woman bitterly jealous of Kirk uses an alien device to exchange her consciousness with his, and then attempts to kill her body and thus Kirk's mind.