- See also BTW's Policy:Canon on how the issue of canonicity should be dealt with on this wiki.
- For a general definition of the term "Canon" in the context of fiction, see Canon.
Canon, with regards to the BattleTech franchise, is the sum of all approved official publications and products that together shape and define the fictional universe that is BattleTech.
It ultimately falls to the owner(s) of an intellectual property (IP) to decide what is part of the same and what is not. Thus, statements, clarifications and rulings made by the BattleTech Line Developer and certain others who are empowered accordingly by the IP owners directly form and affect canon. Fans summarily refer to persons with the power to decide over canon as "The Powers That Be", TPTB for short.
- (edited slightly for improved formatting)
|“|| Whatever we establish for research material for the authors is canon.
Currently, that list includes:
GENERAL INCLUSIVE NOTE: There are a few select instances where a story or article appearing even in these sources may be considered non-canon, but generally this is because the material was in error [...], or it was specifically published as a gag [...].
The list does not include:
GENERAL NON-INCLUSIVE NOTE: Despite their non-canonical status, we have not gone into total denial about these sources either, but have simply opted to pick and choose what elements there are "canon" and what are not.
He also agreed to the following assertion by another poster, stating that "it looks like [the author] has the long and short of it right":
|“|| As long as a piece of fluff from an official source (FASA, FanPro, Catalyst, Infocom*, Activision*, Microprose*, Microsoft*) isn't directly contradicted, and makes sense, you can assume it to be part of the shared universe.
(*Fluff from these sources is 'canon' in the sense that the story that takes place in the game happened in canon in the same general broad strokes - Gideon recovered the Chalice from the Matabushi-backed Dark Wing; Jason found the Star League cache and rescued his father, then fought with the Hounds on Luthien; mercenaries helped Carver V become Liberty, FedCom forces on Port Arthur disrupted Smoke Jaguar operations as part of Operation Bird Dog, etc. - but the details are likely to be significantly different than the ones you experienced during your gameplay).
- For a general definition of the term "Apocrypha" in the context of fiction, see Apocrypha.
"Apocrypha" are products, or the information contained therein, which are neither clearly canonical nor clearly non-canonical. In a broader sense, "apocryphal" is generally used to describe products that were intended to add to the BattleTech universe, but which do not meet the criteria for canon for one reason or another. Although not recognized as canonical, apocryphal sources are invariably official BattleTech products and were produced under a valid license. Thus, they are the official products referred to in the statement above that the IP owners are "not in total denial about these sources either" and that "fluff from an official source [...] that isn't directly contradicted, and makes sense" can be assumed "to be part of the shared universe".
In particular, it applies to the BattleTech products that were explicitly excluded in the above definition of canon despite being official products. Some apocryphal products (such as the BattleTechnology and StarDate magazines) were even canonical originally, but lost that status later on.
Fans tend to ignore the fact that not all official sources are fully canonical, and often accept and treat apocrypha like fully canonical products.
While everything that is not clearly canonical technically falls under non-canon, that term is typically used to describe either of two distinct situations:
Something to do with BattleTech may not be meant to contribute to the BattleTech universe in the first place, like the Critter-TEK parody or a real-world treatise on the BattleTech franchise, or else it is not an official product. The latter category encompasses the vast majority of non-canonical items. Notable examples include the magazines published by fan organizations.
Even the work of people who normally contribute canonical material is considered non-canon if it is done outside of a (canonical) product.
The term Fanon, a portmanteau word blending the words "fan" and "canon", is widely used to describe any unofficial, fan-made content. In this sense, it is frequently used synonymous with "fan fiction" although in the strictest sense of the word, it would only refer to items that have become accepted by the fan base as inferred through canonical information.
Many fan projects (including this wiki) resemble a compilation of canonical information, with little or no original, fan-made content. For the purpose of BTW, such material is known as a Meta-source. It should be noted that a meta-source as such remains non-canonical because it is not an official product, even if put together exclusively from otherwise canonical material.
Information about the BattleTech universe is provided in different ways. Not all canonical information is equally valid within the universe. The 25 Years of Art & Fiction tome first established the distinction between "Story Fiction" ("Novel Fiction" in that particular book, but renamed since) and "Sourcebook Fiction" to adress this issue:
 "Story Fiction": Omniscient perspective
Most BattleTech fiction (novels, scenarios, etc.) is written from an omniscient point of view and thus relates canonically true information to the reader. However, this is only true for information that is provided directly in this omniscient way. By contrast, information is often given indirectly, for example through a message; in this case, only the existence of the message is canonically true, which says nothing about its veracity (see In-universe perspective below).
 "Sourcebook Fiction": In-universe perspective
Sourcebooks and some other publications usually take the form of in-universe documents, i.e. they purport to be reports, messages etc. produced by certain people or factions. As such, they canonically exist within the universe but the information provided therein is naturally prone to inaccuracies, ignorance, bias and attempts at propaganda on the side of the alleged author. Any and all such information may be revealed to be misleading or outright false in later publications.
 Canon Rumors
The Interstellar Players sourcebook was the first to specifically present what became known as Canon Rumors. Canon rumors are myths and urban legends of dubious veracity that canonically exist within the BattleTech universe. Their sourcebook descriptions are delibrately left vague and with several possible explanations, explicitly leaving it to the reader/player to decide what of its content should be taken at face value. It could be said that they provide truly optional canon, although certain canon rumors or parts thereof have been canonically proven true or false in later publications. Others remain ambigous.
 Conflicting information
Truly conflicting information requires two or more omniscient sources ("Novel Fiction") to contradict each other, as only information presented to the reader in this way is invariably true. Omniscient descriptions naturally trump any information that is merely presented as a (possibly inaccurate) information within the universe. A conflict between in-universe sources ("Sourcebook Fiction") would be just that, proving that at least one of them must be wrong without proving any one to be correct.
More detailed information is generally held to trump more general descriptions. In cases where it is impossible to reconcile the conflicting pieces of information, the latest published information supersedes earlier material.
In summary, in the case of contradicting canonical information,
- Novel Fiction trumps Sourcebook Fiction;
- detailed information trumps general information;
- later sources trump earlier sources (see also Retcon below).
- For a general definition of the term "Retcon", see Retroactive continuity
With regards to BattleTech, the word "Retcon" is typically used to describe a change in established canon where a canonical fact/truth is invalidated, typically by substituting it with another fact/truth (sometimes inadvertedly) but in some cases also simply by declaring a given source or piece of information to be non-canon.
The mere addition of information, even for an earlier timeframe, technically constitutes a Retcon under the general definition, but among BattleTech fans it is not perceived as a retcon if it does not alter established canon. The same applies to clarifications and the correction of mere errors such as typos.
A retcon should not be confused with instances where a specific in-universe information is revealed to be incorrect.
Line Developer Herbert A. Beas II postulated a different definition which is more in line with the general definition:
|“||Definition: RETroactive CONtinuity (retcon) - The insertion of material into a work of established canon that explains, supports, or corrects a later development without affecting the greater continuity. This includes adding details to backstory that were not there before (and are explanable as unnoticed or deemed irrelevant at the time), filling in a "blank area" where no information is provided (to back up a present or future development), or erasing/altering a minor detail to accomplish either goal (also referred to as "errata").||”|
Because most information pertaining to the BattleTech universe is presented in the form of in-universe reports, few real retcons (in the sense of changes to canonical information) exist for BattleTech. Prominent examples include:
- The original concept for the 3025 timeline postulated that no functional BattleMech factories remained; the Hesperus II factories were described as gutted and merely a spare parts depot. This concept was abandoned early on, when various operable manufacturing centers were written into the fiction.
- In a similar vein, the availability of Star League era technology prior to the War of 3039 and the later Clan Invasion was gradually retroactively increased. As a result, the initial shock and awe over the fielding of advanced technology in these conflicts became somewhat hard to explain.
- To cope with the canonical import requirements of certain major worlds, the number of operable JumpShips must be significantly higher than the ca. 3,000 registered vessels mentioned in the Mercenary's Handbook 3055; without providing actual numbers, Strategic Operations postulated a much larger number (by at least an order of magnitude).
- Prior to the 3050s, the number and location of the Capellan Confederation' BattleMech factories is inconsistent throughout various sources, though this may also have to do with the question what constitutes a "factory" as opposed to a mere assembly plant or maintenance faciliy, a distinction that is somewhat blurred in the classic Succession Wars era.
- The world of Mica V is consistently described as a barren planet with only a marginal atmosphere where life is only possible within biodomes, yet the BattleCorps story "The Pirate Hunt'" describes it as a lush jungle world. (The author later admitted that he was unaware of the earlier descriptions of Mica V.)
- The nature and backstory for each of several military units includng the Gray Death Legion, the Northwind Highlanders, Hansen's Roughriders and the Amphigean Light Assault Group had several different versions because different authors wrote it independently from and unaware of each other for different canonical products. Ultimately, an authoritative version reconciling the different previous versions was created in each case.