The canon of a work of fiction is "the body of works taking place in a particular fictional world that are widely considered to be official or authoritative; [especially] those created by the original author or developer of the world". Canon is contrasted with, or used as the basis for, works of fan fiction and other derivative works.
When there are multiple "official" works or original media, what material is canonical can be unclear. This is resolved either by explicitly excluding certain media from the status of canon (as in the case of Star Trek and Star Wars), by assigning different levels of canonicity to different media, by considering different but licensed media treatments official and equally canonical to the series timeline within their own continuities' universe, but not across them, or not resolved at all. There is also no consensus regarding who has the authority to decide what is or isn't canon, with copyright holders usually declaring themselves the authorities when they want to erase or retcon materials that were approved by the setting's original creator (with Star Wars again being an example). The use of canon is of particular importance with regard to reboots or re-imaginings of established franchises, such as the Star Trek remake (2009), because of the ways in which it influences the viewer experience.
The official Star Trek website describes Star Trek canon as "the events that take place within the episodes and movies" referring to the live-action television series and films, with Star Trek: The Animated Series having long existed in a nebulous gray area of canonicity. Events, characters and storylines from tie-in novels, comic books, and video games are explicitly excluded from the Star Trek canon, but the site notes that elements from these sources have been subsequently introduced into the television series, and says that "canon is not something set in stone."
During George Lucas' time with the franchise, Star Wars canon was divided into discrete tiers that incorporated the Expanded Universe (EU), with continuity tracked by Lucasfilm creative executive Leland Chee. Higher-tier and newer material abrogated lower-tier and older material in case of contradiction. The live-action theatrical films, the 2008 The Clone Wars TV series and its debut film, and statements by Lucas himself were at the top of this hierarchy; such works invariably superseded EU material in case of contradiction. The EU itself was further divided into several descending levels of continuity. After Disney's acquisition of the franchise, Lucasfilm designated all Expanded Universe material published prior to 25 April 2014 (other than the first six theatrical films and the 2008 The Clone Wars film and TV series) as the non-canonical "Legends" continuity. Material released since this announcement is a separate canonical timeline from the original George Lucas Canon, with all narrative development overseen by the Lucasfilm Story Group.
The makers of Doctor Who have generally avoided making pronouncements about canonicity, with Russell T Davies explaining that he does not think about the concept for the Doctor Who television series or its spin-offs.
The television series The Simpsons has as an example of non-canon material the Treehouse of Horror episodes, a series of Halloween-themed specials with several stories that take place outside the normal continuity of the show.
Several anime television series adapted from manga stories counts with some extra episodes with original stories that are not part of the original manga, often being referred to as "filler episodes", being outside of the canon of their source material.
The canon status of some works by the original writer but not the same publisher, such as "The Field Bazaar", may be debated. This is because copyright used to be exercised by the publisher of the work of literature rather than the author. Campaigning by Victor Hugo led to the Berne Convention which introduced author's rights.
However, sometimes in literature, original writers have not approved works as canon, but original publishers or literary estates of original writers posthumously approve subsequent works as canon, such as The Royal Book of Oz (1921) (by original publisher), Porto Bello Gold (1924) (by estate), and Heidi Grows Up (1938) (by estate).
Late 20th century
In film and television this is common that the original writer does not decide canon. In literature, the estate of H. G. Wells authorised sequels by Stephen Baxter, The Massacre of Mankind (2017) and The Time Ships (1995). Scarlett was a 1991 sequel to Gone with the Wind authorised by the estate.
In 2010, the Conan Doyle estate authorised Young Sherlock Holmes and The House of Silk. Sequels to the stories by P G Wodehouse about the butler Jeeves were sanctioned by Wodehouse's estate for Jeeves and the Wedding Bells (2013) by Sebastian Faulks and Jeeves and the King of Clubs (2018) by Ben Schott. The Monogram Murders (2014) by Sophie Hannah is a sequel to Hercule Poirot novels authorised by the Agatha Christie estate.
Fan fiction is almost never regarded as canonical. However, certain ideas may become influential or widely accepted within fan communities, who refer to such ideas as "fanon", a blend of fan and canon. Similarly, the term "headcanon" is used to describe a fan's personal interpretation of a fictional universe.
- Alternative universe (fan fiction) – Fan fiction set in a non-canonical universe
- Complete works – collection of all the works of one artist, writer, scientist, musician, group, etc.
- Catalogue raisonné – Comprehensive, annotated listing of all the known artworks by an artist
- Continuity (fiction) – Consistency or continuity of narrative
- Expanded universe – Non-linear additions with consistency to the fictional universe
- Fictional universe – Self-consistent fictional setting with elements that may differ from the real world
- Shared universe – Type of fictional universe in which works written by multiple writers are set
- Parallel universes in fiction – Universe coexisting with another universe
- Reset button technique – Plot device that resets continuity in works of fiction
- Sequel – Part of a linear narrative that continues the story of a previous work
- Text corpus – Digital collections of natural language data
- Middle-earth canon – Works of Tolkien set in Middle-earth
- Retroactive continuity – Revision of existing facts in succeeding works of fiction
- Canon of Sherlock Holmes
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- "canon, n.¹, additional sense". Oxford English Dictionary. April 2023. doi:10.1093/OED/8893623977. Retrieved 25 July 2023.
- Romano, Aja (7 June 2016). "Canon, fanon, shipping and more: a glossary of the tricky terminology that makes up fan culture". Vox.com. Retrieved 25 July 2023.
- Urbanski 2013, p. 83.
- "How do the Star Trek novels and comic books fit into the Star Trek universe? What is considered Star Trek "canon"?". startrek.com. CBS Studios. 10 July 2003. Archived from the original on 28 May 2010.
- Baker, Chris (18 August 2008). "Meet Leland Chee, the Star Wars Franchise Continuity Cop". Wired. Retrieved 30 April 2010.
- "The Legendary Star Wars Expanded Universe Turns a New Page". StarWars.com.
- Doctor Who Magazine #388
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- Davies RT, "The Writer's Tales"
- Groening, Matt (2002). The Simpsons season 2 DVD commentary for the episode "Treehouse of Horror" (DVD). 20th Century Fox.
- Ajay Aravind (7 April 2023). "Anime Filler List: What To Skip & What's Worth Watching". Comic Book Resources.
- "Invisible Ink: No 197 - The other Sherlock Holmes writers". The Independent. 3 November 2013.
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- Gardner, Martin (2 May 1971). "We're Off To See The Wizard (Published 1971)". The New York Times.
- "Porto Bello Gold". Library.si.edu.
- "Is Harper Lee's 'Go Set a Watchman' bound for the 'Interstellar' trap?". Los Angeles Times. 4 February 2015.
- Staiger, Janet (1985). "The Politics of Film Canons". Cinema Journal. 24 (3): 4–23. doi:10.2307/1225428. ISSN 0009-7101. JSTOR 1225428.
- "Tell Us 5 Things About Your Book: A Sequel to 'The War of the Worlds' (Published 2017)". 3 September 2017.
- "Tomorrow is another Gone With the Wind sequel". The Guardian. 3 November 2007.
- "Macmillan reveals adventures of young Sherlock Holmes". TheGuardian.com. 18 March 2009.
- Grylls, David (24 October 2020). "Jeeves and the Leap of Faith by Ben Schott, review – a 'new' Wodehouse". The Times.
- "Poirot is a show-off, but he's brilliant. That's why I brought him back to life". the Guardian. 5 November 2017.
- Parrish 2007, p. 33: 'fanon.' Within an individual fandom, certain plotlines may be reinvented so many times and by so many people—or alternately may be written so persuasively by a few writers—that they take on the status of fan-produced canon.
- Romano, Aja (7 June 2016). "Canon, fanon, shipping and more: a glossary of the tricky terminology that makes up fan culture". Vox. Retrieved 19 February 2022.
- Rebecca Black, "Digital Design: English Language Learners and Reader Reviews in Online Fiction", in A New Literacies Sampler, p. 126
- Parrish, Juli J. (2007). "Inventing a Universe: Reading and writing Internet fan fiction". CiteSeerX 10.1.1.93.419.
- Urbanski, Heather (2013). The Science Fiction Reboot: Canon, Innovation and Fandom in Refashioned Franchises. Jefferson, NC: McFarland. ISBN 978-0-7864-6509-5.
- The dictionary definition of canon at Wiktionary