A cliffhanger or cliffhanger ending is a plot device in fiction which features a main character in a precarious or difficult dilemma, or confronted with a shocking revelation at the end of an episode of serialized fiction. A cliffhanger is hoped to ensure the audience will return to see how the characters resolve the dilemma.
An early example of a cliffhanger is found in Homer's epic poem the Odyssey. At the end of Book 4, The Suitors, the villains are setting an ambush for Telemachus, Odysseus' son; the story then moves on to Odysseus' own adventures, and much of the narrative passes before readers can learn Telemachus' fate.
A cliffhanger is a central theme and framing device of the collection of stories known as the One Thousand and One Nights, wherein the queen Scheherazade, who is facing a morning execution on the orders of her husband, King Shahryar, devises the solution of telling him a story but leaving it at a cliffhanger, thus forcing the king to postpone her execution to hear the rest of the tale.
The nineteenth century was a high point in the writing of serialized fiction. At the time, newspapers published novels with one chapter appearing every month. To ensure continued interest in the story, many authors employed techniques appropriate to that medium. Wilkie Collins is famous for saying about the techniques: "Make 'em cry, make 'em laugh, make 'em wait—exactly in that order." He is famous for the Sensation Novel, which relied heavily upon the cliffhanger. Examples of his endings include: "The next witnesses called were witnesses concerned with the question that now followed—the obscure and terrible question: Who Poisoned Her?" (The Law and the Lady) "Why are we to stop her, sir? What has she done?" "Done! She has escaped from my Asylum. Don't forget; a woman in white. Drive on." (The Woman in White) "You can marry me privately today," she answered. "Listen--and I will tell you how!" (Man and Wife)"
This anticipation and conversation-inducing authorial technique would often be very contrived as the only purpose was to maintain interest in the monthly serial. Therefore, these were regularly removed from the plot when the serial was published as a full novel. The cliff-hanger migrated to film and is best known from the popular silent film series The Perils of Pauline (1914), shown in weekly installments and featuring Pearl White as the title character, a perpetual damsel in distress who was menaced by assorted villains, with each installment ending with her placed in a situation that looked sure to result in her imminent death – to escape at the beginning of the next installment only to get into fresh danger at its end. Specifically, an episode filmed around the New Jersey Palisades ended with her literally left hanging over a cliff and seemingly about to fall. A history of the cliffhanger and important stages of serial narration was written by Vincent Fröhlich in German.
Cliffhanger commercials have become a thing. A commercial with a discernable plot and attempt at creating curiosity and then guiding the viewer to the website of the company (or an associated company). A diamond commercial from 2005 is the earliest use of this technique. 
Cliffhangers were especially popular in 1920s and 1930s serials when movie theaters filled the cultural niche now primarily occupied by television. Cliffhangers are often used in television series, especially soap operas that end each episode on a cliffhanger. Prior to the early 1980s, season-ending cliffhangers were rare on U.S. television. The first such season-ender on U.S. TV was in the comedy send-up of soap operas Soap in 1978. Several Australian soap operas, which went off air over summer, such as Number 96, The Restless Years, and Prisoner, ended each year with major and much publicized catastrophe, such as a character being shot in the final seconds of the year's closing episode.
Cliffhangers were rare on American television before 1980, as television networks preferred the flexibility of airing episodes in any order. The phenomenal success of the 1980 "Who shot J. R.?" third season-ending cliffhanger of Dallas, and the "Who Done It" fourth-season episode that finally solved the mystery, contributed to the cliffhanger becoming a common storytelling device on television. Another notable cliffhanger was the "Moldavian Massacre" on Dynasty in 1985, which fueled speculation throughout the summer months regarding who lived or died when almost all the characters attended a wedding in the country of Moldavia, only to have revolutionaries topple the government and machine-gun the entire wedding party.
On British TV, cliffhangers had been used regularly since the 1960s (and, to lesser extent 70s and 80s), such as in the hit BBC1 science fiction show Doctor Who.
The two main ways for cliffhangers to keep readers/viewers coming back is to either involve characters in a suspenseful, possibly life-threatening situation, or to feature a sudden shocking revelation.
Cliffhangers are also used to leave open the possibility of a character being killed off due to the actor not continuing to play the role.
Cliffhangers are also sometimes deliberately inserted by writers who are uncertain whether a new series or season will be commissioned, in the hope that viewers will demand to know how the situation is resolved. Such was the case with the second season of Twin Peaks, which ended in a cliffhanger similar to the first season with a high degree of uncertainty about the fate of the protagonist, but the cliffhanger could not save the show from being canceled, resulting in the unresolved ending.
The cliffhanger has become a genre staple (especially in comics, due to the multi-part storylines becoming the norm instead of self-contained stories). To such a degree, in fact, that series writers no longer feel they have to be immediately resolved, or even referenced, when the next episode is shown. variously because the writer didn't feel it was "a strong enough opener," or simply "couldn't be bothered." The heavily serialized television drama True Blood has become notorious for cliffhangers. Not only do the seasons conclude with cliffhangers, but almost every episode finishes at a cliffhanger directly after or during a highly dramatic moment.
Commercial breaks can be a nuisance to script writers because some sort of incompleteness or minor cliffhanger should be provided before each to stop the viewer from changing channels during the commercial break. Sometimes a series ends with an unintended cliffhanger caused by a very abrupt ending without a satisfactory dénouement, but merely assuming that the viewer will assume that everything sorted itself out.
Sometimes a movie, book, or season of a television show will end with the defeat of the main villain before a second, evidently more powerful villain makes a brief appearance (becoming the villain of the next film).
- Verdon, Joan (03/05/2012). "A hike back in time to era of silent film". The Record. p. L-6. Check date values in:
- Meisler, Andy (1995-05-07). "TELEVISION; When J. R. Was Shot The Cliffhanger Was Born". The New York Times. Retrieved June 14, 2012.
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- Vincent Fröhlich: Der Cliffhanger und die serielle Narration. Bielefeld: Transcript Verlag, 2015. ISBN 978-3837629767.