- For policy information for how we deal with canon on this wiki, see Tardis:Canon policy.
Canon is a fan-based idea that exists in a unique way within Doctor Who fandom. In theory, it means a body of work that an established body of literature that can draw upon, but it is more commonly thought as what a fan considers what forms part of the Doctor Who universe, or what "really happened". This is often a personal choice, one which is endlessly discussed and argued about in just about every Doctor Who-related forum or message board that has existed on the internet. Unlike the Star Trek and Star Wars universes, the British Broadcasting Corporation (BBC) has never made a pronouncement about what is or is not canon for Doctor Who. In August 2010 however, the BBC did make a fleeting reference to canon, in relation to their Doctor Who: The Adventure Games, stating in their press release that "Players will encounter new and original monsters, in stories which form part of the overall Doctor Who canon".  A large issue when attempting to construct a definition of canon for Doctor Who is that it is never finished; Doctor Who has been in more or less constant production in one way or another since 1963, what with TV stories, novelisations, novels, radio dramas, audio stories, toys, comic stories and so much more. Some fans want a complete narrative, but Doctor Who can never be complete. 
Canon can be defined as the body of cultural/narrative history of Doctor Who that everything narratively Doctor Who related is canon, from the annuals to the audio stories, their ideas, their history filters down through their stories becomes part of the larger Doctor Who universe. With writers being influenced or referencing this body of work as they create new stories. This can also be seen as continuity, which is roughly the interconnectedness of stories and how they're referenced in each story.
As a narrative history, that it exists is enough to consider it canon, the ideas and themes, forms and designs filter down through the stories, with elements making their way into future productions. The Dalek space craft of The Dalek Chronicles were worked into CGI replacement shots on the DVD of The Dalek Invasion of Earth and then further into television stories such as The Parting of the Ways. Again this can merely be an example of continuity within the show rather than as an established canon.
Throughout Doctor Who's production there have always been 'competing narratives'; stories produced across several mediums that used the TV-created characters, in the 1960s and 70s these took the form of short stories and comic stories produced in annuals and comic strips. In the 1980s Doctor Who Magazine joined the fray with their own comic strip based stories and as the annuals did and continued to do short fiction was also produced for the magazine.
During the 1990s Doctor Who as a brand shifted and fragmented with the end of television production, with multiple Doctor Who spin-offs being produced by fans and novel series published by Virgin Books continuing the Doctor's travels beyond its TV realm. Concurrently, the TV series was analysed in detail, academics unearthing long undiscovered materials about the genesis of the show, and the official history of the Doctor Who series was greatly expanded upon within a postmodern context. 
There have been deliberate moves to create separate canons of Doctor Who, the earliest example of this are the two movies of the 1960s, staring Peter Cushing Dr. Who and the Daleks and Daleks' Invasion Earth 2150 A.D. make no effort to be a part of what even at that point was "established", with none of the Doctor Who elements, aside from the police box and the Daleks appearing in their accepted form. These stories however still "exist" and have not been ignored by even the BBC with a short story appearing in the BBC Books short story anthology Short Trips and Side Steps featuring a story featuring Dr Who. Other examples are evidenced with an official shift in definition, 2003's Scream of the Shalka was to have been the continuation of Doctor Who, with Richard E. Grant promoted as the "new" Ninth Doctor. The BBC's first edition of Doctor Who: The Legend even has several pages which details the "Ninth Doctor". But this detail was changed and the "Shalka Doctor" shifted away from what was considered to be part of the Doctor Who history with the arrival of the new BBC Wales series.
- ↑ 1.0 1.1 Philip Sandifer (Wednesday, March 16, 2011). You Were Expecting Someone Else II (1966 Annual, The Dalek Book, Dalek World). TARDIS Eruditorum: A Psychochronography in Blue. Retrieved on 22nd October 2011.
- ↑ Paul Cornell (Feb 10 2007). Canonicity in Doctor Who. PaulCornell.com. Retrieved on 22nd October 2011.
- ↑ BBC unveils Doctor Who – The Adventure Games. BBC - Press Office (08.04.2010). Retrieved on 22nd October 2011.
- ↑ Magrs, Paul, (2007), "Afterword - My Adventures", Time and Relative Dissertations in Space, Manchester University Press, Manchester, UK, &, Room 400, New York, USA, p.302
- ↑ Frank Collins. DOCTOR WHO The Transmedia Experience. Television Heaven. Retrieved on 22nd October 2011.
- ↑ Jon Preddle (December 2000). Short Trips and Side Steps: A Collection of Short Stories - Book review. NZDWFC. Retrieved on 22nd October 2011.
- ↑ BBCi's Ninth Doctor. BBC - News. bbc.co.uk (11 July 2003). Archived from the original on August 15 2006. Retrieved on 22nd October 2011.