"Is There in Truth No Beauty?" is a third season episode of the original science fiction television series, Star Trek, first broadcast October 18, 1968. It is episode No. 60, production No. 62, written by Jean Lisette Aroeste, and directed by Ralph Senensky. In this episode, the Enterprise travels with an alien ambassador whose appearance induces madness.

The starship USS Enterprise is assigned to escort a Medusan ambassador named Kollos to the Federation to engage in trade route discussions. Medusans are energy-based creatures that are emotionally beautiful inside but whose outward appearance causes humanoids to go insane. For the transit, Kollos offers to stay in a special vessel to protect the crew of the ship; First Officer Spock has offered to assist as necessary using a specially designed visor which allows his Vulcan psychology to withstand Kollos' appearance. Kollos is accompanied by Lawrence Marvick, one of the designers of the Enterprise, and Dr. Miranda Jones, Kollos' beautiful assistant who is also a telepath. Spock is taken by Jones' beauty and her ability to observe Kollos without its maddening effects. During early conversations, she is impressed by Spock's own telepathic abilities, as they are far stronger than her own.

At a private dinner with Captain Kirk, Jones falls ill, sensing someone aboard with murderous intentions, but does not know the target. Jones returns to her quarters, where she is later visited by Marvick. It is revealed that Marvick intends to kill Kollos as he is madly in love with Jones, a feeling which she does not reciprocate. Shunned and vengeful, Marvick makes his way to Kollos with a phaser to follow through with the murder attempt, but before he can pull the trigger, he looks directly upon Kollos' true form. Now in the clutches of insanity, Marvick rushes to Engineering, knocks out Chief Engineer Scott and other crew members, and reprograms the engines. The Enterprise quickly accelerates to Warp Factor 9, which soon takes it far outside of the galaxy before the other crew members can regain control and restrain Marvick. Marvick wildly screams accusations at Jones before he dies.

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