Warren Stevens as Rojan: "I am your commander, from this moment on."

Warren Stevens: "Any efforts to resist us or to escape will be severely punished."

Warren Stevens: "You humans must face the end of your existence."

James Doohan as Mr. Scott: "All I have is a bottle of very, very, very old Scotch... whisky!"

Sound effects from the bridge of the Enterprise.

Morgan Woodward at Capt. Tracey: "How long would a man live if all disease were erased?"

Deforest Kelley as McCoy: "Hard to believe we were once foolish enough to play around with that."

Kelley: "I've found that evil usually triumphs, unless good is very, very careful."

Roy Jenson as Cloud William: "It is written... good must destroy evil."

Woodward: "Are you grasping all it means?"

Kelley: "Our tissues definitely show a massive infection."

Woodward: "I'll contact you later – let you know of any future needs."

Kelley: "Leave medicine to medical men. You've found no fountain of youth here!"

Music played during many of the shows dramatic scenes, often during hand-to-hand combat."

Music played during semi-dramatic interludes.

Music played when someone is surprised or startled.

Morgan Woodward: "Suppose we go on to the next subject."

Leonard Nimoy as Spock: "He was less than truthful in one very important matter."

William Shatner as Kirk: "All this is for nothing!"

Shatner: "Pity you can't teach me that."

Nimoy: "I have tried, Captain."

(in reference to the Vulcan neck pinch)

Shatner: "A star captain's most solemn oath is that he will give his life – even his entire crew – rather than violate the Prime Directive."

Shatner: "Enterprise..."

SFX: Kirk tapping the communicator.

Shatner: "Do you read me?"

Shatner: "Do you see any hope that these Yangs can be reasoned with?"

Woodward: "We must have a doctor researching this."

Woodward: "You'll stay alive only as long as you stay here."

George Takei as Sulu: "Surely you know that can't be done without verification."

Nimoy: "They seem incredibly vicious."

Shatner: "Why?"

Shatner: "Liberty and freedom have to be more than just words."

SFX: Hailing whistle.

Nichelle Nichols as Uhura: "Bridge to Captain Kirk."

William Shatner as Kirk: "Kirk here. What is it?"

DeForest Kelley as McCoy: "Dunsel? Who the blazes is Capt. Dunsel?"

William Shatner as Captain Kirk: "I need communications!"

Leonard Nimoy as Spock: "The most ambitious computer complex ever created."

Nimoy: “I hold an A-7 computer expert classification.”

Leonard Nimoy: "The computer can process information, but only the information which is put into it."

(Thanks, Greg, for identifying this sound bite as coming from this episode.)

Nimoy: “Computers make excellent and efficient servants, but I have no wish to serve under them.”

Nimoy: “I simply maintain that computers are more efficient than human beings – not better.”

William Shatner: "Cut power!"

Kelley: “This thing is a danger to all of us! Now find some way to shut it off!”

Shatner: "They've just signed their own death warrant!"

Shatner: "Disengage this computer now."

Nimoy: “This is not a drill.”

Walter Koenig as Ensign Chekov: “ETA, five minutes.”

Leonard Nimoy: "Most illogical."

DeForest Kelley: "Please, Spock, do me a favor and don't say it's fascinating."

Leonard Nimoy: "No... But, it is interesting."

William Marshall as Dr. Richard Daystrom: “No! We’re invincible! Look what we’ve done!”

Marshall: “Colleagues laughing behind my back at the boy wonder... and becoming famous, building on my work... building on my work!”

Marshall: “As I suspected. It is not a malfunction.”

Shatner: “There are certain things men must do to remain men.”

Nichelle Nichols as Uhura: “Priority message coming in, Sir.”

Shatner: “Put it on audio.”

SFX: Beep!

Nichols: “Captain, message now coming in from Commodore Wesley.”

Shatner: “Put it on visual.”

SFX: Beep!

Nimoy: “You’re using an entirely new type of control mechanism; however, it appears to me this unit is drawing more power than before.”

James Doohan as the voice of the M-5 computer: “Murder is contrary to the laws of man and God.”

Dramatic music often used in the series to indicate an escalating conflict followed by a sudden resolution.

(Sound effects for photon torpedoes being fired can be heard in the background.)

Music often played to indicate a rising tension.

James Doohan as the voice of the M-5 computer: “This... unit... must... die.”

Doohan: "This unit is the ultimate achievement in computer evolution. This unit must survive."

Kelley: “Jim, he’s on the edge of a nervous breakdown, if not insanity!”

Nimoy: “Doctor, this unit is not a human body.”

Marshall: “One machine can do all those things they send men out to do now.”

Koenig: "Moving back to original course and speed."

George Takei as Sulu: “We’re coming back on our original course, Captain.”

Marshall: “There are other things a man like you might do.”

Barry Russo as Commodore Bob Wesley: “Phasers on target.”

Shatner: “Only a fool would stand in the way of progress, if this is progress.”

William Shatner: "Pull out the plug, Spock."

Marshall: "Quite right!"

Marshall: “I’m going to show you. I’m going to show all of you.”

James Doohan as Mr. Scott: "Captain, I've located the source of the power shut-down!"

Nimoy: “Every living thing wants to survive, Captain.”

William Shatner: "All I... ask is a tall ship and a... star... to steer her by."

James Doohan: "Captain, what do we do??"

Leonard Nimoy as Spock: "It appears, Captain, we've been doing what used to be called pursuing a wild goose."

Shatner: “I think that thing is wrong... and, I don’t know why.”