The 56th episode of Gene Roddenberry’s science fiction series Star Trek airs on NBC. This is the first episode of the third season, and the first overseen by new producer Fred Freiberger. Marj Dusay guest stars. 
Stardate 5431.4: The Enterprise is intercepted by a starship of unknown design and a woman from the ship beams directly into the bridge and uses a device to render the Enterprise’s crew unconscious. She then walks over to Spock… When the crew awakens, McCoy summons Kirk to sick bay and informs him that the alien visitor apparently removed Spock’s entire brain without even performing surgery. After Spock’s body is fitted with a device that allows McCoy to control the Vulcan’s motor functions with a remote control, Kirk starts a search for Spock’s brain, hoping it can be recovered and somehow returned to Spock before his body decays.
written by Lee Cronin
directed by Marc Daniels
music by Fred SteinerCast: William Shatner (Captain James T. Kirk), Leonard Nimoy (Mr. Spock), DeForest Kelley (Dr. Leonard McCoy), James Doohan (Mr. Scott), George Takei (Lt. Sulu), Nichelle Nichols (Lt. Uhura), Walter Koenig (Chekov), Marj Dusay (Kara), Majel Barrett (Nurse Chapel), James Daris (Creature), Sheila Leighton (Luma)
Notes: Generally considered one of the original Star Trek’s lowest ebbs, Spock’s Brain – and every other third season episode attributed to “Lee Cronin” – actually came from the pen of Gene L. Coon, who has laid much of the series’ groundwork, including the Klingons and the Prime Directive.
LogBook entry by Earl Green