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The '''canon''' of the Half-Life and Portal universe|''Half-Life'' and ''Portal'' series has never been officially defined by Valve. Series writer Marc Laidlaw stated that the issue of canon is "something the fans came up with"http// Marc Laidlaw as quoted in the ''Marc Laidlaw Vault'' on the Steam Users' Forums and that they do not have an official stance on it.{{cite web |title=Canonicity of games in the Half-Life series (archived)|url=http//|publisher=Crowbar Error 42|accessdate=2009-10-29|date=September 2009}} He remarked that they "do not get involved in issues of canonicity" and that "canon itself is non-canon", letting the games stand on their own. Valve also chooses not to define a precise timeline as they would only end up contradicting themselves in the future.http// ''Marc Laidlaw Vault'' on the Forums As such, a handful of retcons have occurred throughout the series.

==OverWiki designations rationale==
As no official definition of canon exists for the ''Half-Life'' and ''Portal'' series, the use of the term "canon" here on the Combine OverWiki is meant strictly for browsing convenience purposes to distinguish between sources that contribute to the series' overarching storyline and sources that do not. The following list is not official and should not be taken as rule.

==Unofficial OverWiki list==
===Canon material===
*''Half-Life Opposing Force''
*''Half-Life Blue Shift''
*''Half-Life Decay''
*''Half-Life 2''
*''Half-Life 2 Episode One''
*''Half-Life 2 Episode Two''
*''Portal 2''
*''Peer Review''
*''Perpetual Testing Initiative ''
*''Portal 2 Lab Rat''
*The Portal ARG|''Portal'' ARG
*The PotatoFoolsDay ARG|''PotatoFoolsDay'' ARG
*The Marc Laidlaw Vault on the http// Steam User's Forums (latest version) and http// Forums {{C|Collection of e-mails from series' writer Marc Laidlaw and other developers revealing additional information}}

====The official guides====
*''http// Half-Life Prima Guide''
*''http// Half-Life Opposing Force Prima Guide''
*''http// Half-Life 2 Prima Guide''
*''http// Half-Life 2 Episode One Prima Guide''
*''http// The Orange Box Prima Guide''
*''http// Portal 2 The Official Guide'' {{C|Standard and collector}}

===Non-canon material===
*Every game trailer, as they contain most of the time elements that have been changed for the game's release
*''Codename Gordon''
*''Deathmatch Classic''
*''Half-Life Deathmatch Source''
*''Half-Life 2 Deathmatch''
*''Half-Life 2 Survivor''
*''Portal Still Alive''
*Portal 2 Sixense MotionPack DLC|''Portal 2'' Sixense MotionPack DLC

====Cut material====
*Anything related to the pre-release versions of the games (such as the leaked ''Half-Life'' alpha and the ''Development of Half-Life 2|Half-Life 2 leak'')
*''Half-Life'' {{C|Turned into ''Half-Life''}}
*''Get Your Free TVs!''
*''Half-Life Uplink''
*''Half-Life 2 Lost Coast''
*''Directed Design Experiments experiment F-STOP|F-STOP'' {{C|Turned into ''Portal 2''}}

====Behind the scenes media====
*''Half-Life 2 Raising the Bar''
*''The Final Hours of Portal 2''

==See also==
*Timeline of the Half-Life and Portal universe|Timeline of the ''Half-Life'' and ''Portal'' universe


==External links==
*WikipediaCanon (fiction)|Canon on Wikipedia

CategoryReal world