- "I would draw some of the great tales in fullness, and leave many only placed in the scheme, and sketched. The cycles should be linked to a majestic whole, and yet leave scope for other minds and hands, wielding paint and music and drama."
- —J.R.R. Tolkien
There are various reasons for the matter of what is authoritative to be confusing:
- Tolkien worked on Middle-earth over the course of decades, making substantial changes. Readers may remember, for example, the differences between The Hobbit and The Lord of the Rings with regard to Gandalf and the Elves. Moreover, toward the end of his life the focus of his writing shifted from pure storytelling to more philosophical concerns, which rendered a shift in tone and content.
- Tolkien's writing is laden with details and hints, which can be contradictory, especially in posthumously published works. Such information should not take precedence over more explicit statements elsewhere, but it can help to flesh out one's understanding of Middle-earth even if confusing. In general, the revised versions of The Hobbit and the Lord of the Rings are considered canon, but with The Silmarillion and other posthumous texts the matter is more complex.
- In The History of the Middle-earth and Unfinished Tales, Christopher Tolkien admits in hindsight that some content of The Silmarillion were his or Guy Gavriel Kay's inventions, and not wholly Tolkien's ideas. He occasionally discusses some things he would have done differently if editing the book a second time. Certain materials which he 'ignored' or tossed out he realized in hindsight would have been fairly easy to manage.
- In some cases, Tolkien had even intentionally left some gaps in his works. In one of his letters (#144) he provided both an explanation and an example of this, writing concerning Tom Bombadil that "even in a mythical Age there must be some enigmas, as there always are. Tom Bombadil is one (intentionally)." Giving an incomplete picture in this way can be frustrating, but it also makes the invented world feel more natural.
- I am doubtful myself about the undertaking. Part of the attraction of The Lord of the Rings is, I think, due to the glimpses of a large history in the background: an attraction like that of viewing far off an unvisited island, or seeing the towers of a distant city gleaming in a sunlit mist. To go there is to destroy the magic, unless new unattainable vistas are again revealed. Also many of the older legends are purely 'mythological', and nearly all are grim and tragic: a long account of the disasters that destroyed the beauty of the Ancient World, from the Darkening of Valinor to the Downfall of Númenor and the flight of Elendil.
- - from The Letters of J.R.R. Tolkien, letter 247
For the purposes of this wiki, canon will be defined as anything pertaining to Middle-earth that was written/invented by J.R.R. Tolkien or developed under license from Tolkien Enterprises. Although elements of the latter will be regarded as non-canon relative to Tolkien's works, they are both officially approved by his estate and internally consistent with themselves and any other directly related works. For example, the three films comprising the Jackson trilogy are internally consistent with each other and licensed by Tolkien Enterprises, so they may be included if the information from these films is clearly indicated to be derived from Jackson's work, as opposed to Tolkien's work, by being placed under the "Portrayal in Adaptations" section of an article. Should some element of an adaptation be unique to that adaptation, however, and not found in Tolkien's works, it is still permitted, but is considered and must clearly be categorised as non-canon, and labeled so with the "NonCanon" template.
Non-canon vs. "Precanon" vs. external mythologies
On this wiki, if an article's topic is non-canonical from the start, the article will be categorized and labeled as such. The same goes for few topics of Middle-earth lore that are here considered not non-canonical but precanonical - for example, any topics indigenous to the story of Eriol, a character who originates from a real location (England) and is thus only semi-invented, or such as the villain Tevildo, the forerunner to the idea of Sauron, or such as Kullervo, a character who originates from Finnish Mythology and yet in the publication summary to The Story of Kullervo is referred to as "..the darkest and most tragic of all Tolkien's characters."
Unlike the English and Finnish mythological elements mentioned above, the book Finn and Hengest is not considered precanonical or non-canonical. It is a study, narration, and interpretation by Tolkien of two characters who appear in two different Old English poems. The same goes for The Legend of Sigurd and Gudrún, another work published under Tolkien's name that contains narrative directly originating from Norse Mythology.
Most but not all lore discussed on articles in a section labeled "Earlier Versions of the Legendarium" concern precanonical events or story-lines. As signified by that section heading, topics that are precanonical still are counted as part of the legendarium, whereas all non-canonical topics are not.
On this wiki, there is no category exclusively for all things that are canon, for those make up the main space of the encyclopedia. With the three exceptions of Wiki policies, all writings of J.R.R. Tolkien, and all other Real World topics (Real people, books, websites, games, etc.), informative articles on this Wiki that have no categories with the word "canon" in them are canonical, and pertain to the "true" and final version of the legendarium of Middle-earth.