Tomorrow Is Yesterday

"Tomorrow Is Yesterday"
Star Trek: The Original Series episode
Screenshot from the show's opening teaser of an F-104C Starfighter
Episode no.	Season 1 Episode 19
Directed by	Michael O'Herlihy
Written by	D. C. Fontana
Featured music	Alexander Courage
Cinematography by	Jerry Finnerman
Production code	021
Original air date	January 26, 1967 (1967-01-26)
Guest appearances
Roger Perry – USAF Captain John Christopher Hal Lynch – USAF Air Police Sergeant Richard Merrifield – Technician John Winston – Transporter Chief Kyle Ed Peck – USAF Air Police Col. Fellini Mark Dempsey – Air Force Captain Jim Spencer – USAF Air Policeman Sherri Townsend – Crew Woman
Episode chronology
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Star Trek: The Original Series season 1
List of episodes

"Tomorrow Is Yesterday" is the nineteenth episode of the first season of the American science fiction television series Star Trek. Written by D. C. Fontana and directed by Michael O'Herlihy, it first aired on January 26, 1967.^[1] It was the first Star Trek episode to be written solely by a woman (Fontana had previously written the teleplay for the episode “Charlie X” but the story was credited to Gene Roddenberry).

In the episode, the Enterprise is sent back in time to Earth in the 1960s, where the US Air Force detects it. The crew must correct the damage to the timeline and find a way to travel back to the future.