Leonard Nimoy: "If I want anything from you, I'll ask for it!"

William Shatner: "Bones, I'm a busy man."

Sfx: Communicator.

Leonard Nimoy: "I should like to request a leave of absence."

William Shatner as Captain James T. Kirk: "Are you a doctor, or aren't you?"

Leonard Nimoy: "What is this??"

Leonard Nimoy as Spock: "Ask me no further questions – I will not answer!"

DeForest Kelley as McCoy: "Get your hands off of him, Spock!"

Leonard Nimoy: "Logical. Flawlessly logical."

Walter Koenig as Chekov: "I think I'm going to get space sick."

Leonard Nimoy: "Yes or no!"

Kelley: "When I suggested to Spock that it was time for his routine check-up, your logical, unemotional first officer turned to me and said, 'You will cease to pry into my personal matters, Doctor, or I shall certainly break your neck.' "

Leonard Nimoy as Spock: "Approximate age: four billion years."

Leonard Nimoy: "Class M-type planet. Oxygen-nitrogen atmosphere."

William Shatner as Kirk: "Could you get that excited over a cup of coffee?"

Leonard Nimoy: "Sensors indicate no life forms."

DeForest Kelley as McCoy: "I'm not sure I like that, Jim."

Kelley: "One day she'll find the right man and off she'll go."

Leonard Nimoy: "In all respects, quite ordinary, Captain."

Kelley: "He thinks he's the right man for her, but I'm not sure she thinks he's the right man."

Leonard Nimoy as Spock: "They will not answer."

William Shatner as Kirk: "Captain's log, stardate 3541.9"

Leonard Nimoy: "We would've known in advance of any system-wide catastrophe."

Vic Perrin as the voice of Nomad: "The knowledge banks of this unit have been wiped clean."

DeForest Kelley as McCoy: "He's dead, Jim."

Leonard Nimoy as Spock: "Error... flaw... imperfection."

Vic Perrin as the voice of Nomad: "You are in error. You are a biological unit. You are imperfect."

Leonard Nimoy: "I register no life readings at all, sir."

Nichelle Nichols as Uhura: "There's nothing, sir. I'm scanning all frequencies."

Leonard Nimoy: "Error... flaw... imperfection... must sterilize."

Leonard Nimoy: "The long-range sensor sweep of this system reveals no sign of life."

DeForest Kelley: "It's unbelievable."

Leonard Nimoy: "Fascinating."

Leonard Nimoy: "Dazzling display of logic."

Leonard Nimoy: "This is no ordinary machine, Captain. It may well possess a rudimentary intelligence."

Leonard Nimoy: "Captain, I suggest the Vulcan mind probe."