"You unlock this door with a key of imagination. Beyond it is another dimension; a dimension of sound, a dimension of sight, and a dimension of mind. You are moving into a land of both shadow and substance, of things and ideas. You have just crossed over into The Twilight Zone."

The Twilight Zone is an anthology television series created by Rod Serling, who also served as the host and wrote or adapted a majority of the scripts during its original 1959-1964 run on CBS. The series became renowned for its surreal nature and its frequent use of surprise endings, as well as its distinctive theme music. The use of allegorical speculative fiction allowed Serling to touch on subject matter which television executives of the day would have been uneasy seeing on a series with a more mundane setting. Some of its more renowned episodes include: "Time Enough at Last" (starring Burgess Meredith), "Nightmare at 20,000 Feet" (starring William Shatner in one of two appearances), and "To Serve Man" (featuring Richard Kiel).

As well as the original series, a movie was released in 1983. It starred Burgess Meredith as the narrator and featured adaptations of three episodes of the original series (including the above mentioned "Nightmare at 20,000 Feet"), as well as an original story. In 1994, a TV movie entitled Twilight Zone: Rod Serling's Lost Classics aired, hosted by James Earl Jones. It featured a recently unearthed teleplay written by Serling and was paired with another story written by Richard Matheson. There have also been three revivals. The first aired on CBS 1985-1989, with Charles Aidman as host for the first two seasons and Robin Ward for the third. The second revival aired on UPN in 2002-2003 and was hosted by Forest Whitaker. The third revival produced two seasons (2019-2020) for the CBS All Access streaming service (now Paramount+) and was hosted by Jordan Peele.

The Twilight Zone is regularly alluded to on Mystery Science Theater 3000, both in the theater and during the host segments. Additionally, many of the actors in the films used on the show have also worked on The Twilight Zone and Star Trek. It has been inspirational to and paid tribute to on other serialized SciFi-Horror-Fantasy shows such as The X-Files, Twin Peaks and Stargate SG-1.