||This article's lead section may not adequately summarize key points of its contents. (June 2012)|
|Type||Subsidiary of ZeniMax Media|
|Industry||Computer and video games
|Founded||Mesquite, Texas, U.S.
(February 1, 1991)
|Headquarters||Richardson, Texas, U.S.|
|Key people||John Carmack, Technical Director
Todd Hollenshead, President
Kevin Cloud, Executive Producer
Tim Willits, Creative Director
|Products||See complete products listing|
ZeniMax Media Inc. (2009-present)
Id Software LLC (//, see Company Name) is an American video game development company with its headquarters in Richardson, Texas. The company was founded in 1991 by four members of the computer company Softdisk: programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack (no relation to John Carmack). Business manager Jay Wilbur was also involved.
Id was responsible for some of the biggest technological breakthroughs of video game technology for the PC (running MS-DOS and Windows). Starting with the Wolfenstein 3D franchise and continuing with the Doom and Quake franchises, Id pushed the boundaries of video game technology—particularly 3D computer graphics technology—and created game engines that are heavily used throughout the video game industry.
On June 24, 2009, ZeniMax Media acquired the company.
The founders of Id Software met in the offices of Softdisk developing multiple games for Softdisk's monthly publishing. These included Dangerous Dave and other titles. In September 1990, John Carmack developed an efficient way to perform rapid side-scrolling graphics on the PC. Upon making this breakthrough, Carmack and Hall stayed up late into the night making a replica of the first level of the popular 1988 NES game Super Mario Bros. 3, inserting stock graphics of Romero's Dangerous Dave character in lieu of Mario. When Romero saw the demo, entitled "Dangerous Dave in Copyright Infringement", he realized that Carmack's breakthrough could have potential, the team that would later form Id Software immediately began moonlighting, going so far as to "borrow" company computers that were not being used over the weekends and at nights while they designed their own remake of Super Mario Bros. 3.
Despite their work, Nintendo turned them down, saying they had no interest in expanding to the PC market, and that Mario games were to remain exclusive to Nintendo consoles. Around this time, Scott Miller of Apogee Software learned of the group and their exceptional talent, having played one of John Romero's Softdisk games, Dangerous Dave, and contacted Romero under the guise of multiple fan letters that Romero came to realize all originated from the same address. When he confronted Miller, Miller explained that the deception was necessary since companies at that time were very protective of their talent and it was the only way he could get Romero to initiate contact with him. Miller suggested that they develop shareware games that he would distribute. As a result, the Id Software team began the development of Commander Keen, a Mario-style side-scrolling game for the PC, once again "borrowing" company computers to work on it at odd hours at the lake house at which they lived in Shreveport, Louisiana. On December 14, 1990, the first episode was released as shareware by Miller's company, Apogee, and orders began rolling in. Shortly after this, Softdisk management learned of the team's deception and suggested that they form a new company together, but the administrative staff at Softdisk threatened to resign if such an arrangement were made. In a legal settlement, the team was required to provide a game to Softdisk every two months for a certain period of time, but they would do so on their own. On February 1, 1991, Id Software was founded.
The shareware distribution method was initially employed by Id Software through Apogee Software to sell their products, such as the Commander Keen, Wolfenstein and Doom games. They would release the first part of their trilogy as shareware, then sell the other two installments by mail order. Only later (about the time of the release of Doom II) did Id Software release their games via more traditional shrink-wrapped boxes in stores (through other game publishers).
On June 24, 2009, it was announced that Id Software had been acquired by ZeniMax Media (owner of Bethesda Softworks). The deal would eventually affect publishing deals Id Software had before the acquisition, namely Rage, which was being published through Electronic Arts.
Company name 
The company writes its name with a lowercase id, which is pronounced as in "did" or "kid", and in the book, Masters of Doom, it is said that the group identified itself as "ideas from the deep" in the early days of Softdisk, but in the end the name 'id' came from the phrase, "in demand." It is presented by the company as a reference to the Id, a psychological concept introduced by Sigmund Freud. Evidence of the reference can be found as early as Wolfenstein 3D with the statement "that's id, as in the id, ego, and superego in the psyche" appearing in the game's documentation. Even today, Id's History page makes a direct reference to Freud.
Original owners 
- John Carmack, technical director
- John Romero, level artist
- Adrian Carmack, artist
- Tom Hall, Game designer
Game development 
Starting with their first shareware game series, Commander Keen, Id Software has licensed the core source code for the game, or what is more commonly known as the engine. Brainstormed by John Romero, Id Software held a weekend session titled "The Id Summer Seminar" in the summer of 1991 with prospective buyers including Scott Miller, George Broussard, Ken Rogoway, Jim Norwood and Todd Replogle. One of the nights, Id Software put together an impromptu game known as "Wac-Man" to demonstrate not only the technical prowess of the Keen engine, but also how it worked internally.
Id Software has developed their own game engine for each of their titles when moving to the next technological milestone, including Commander Keen, Wolfenstein 3D, ShadowCaster, Doom, Quake, Quake II, and Quake III, as well as the technology used in making Doom 3. After being used first for Id Software's in-house game, the engines are licensed out to other developers. According to Eurogamer.net, "Id Software has been synonymous with PC game engines since the concept of a detached game engine was first popularised". During the mid to late 1990s, "the launch of each successive round of technology it's been expected to occupy a headlining position", with the Quake III engine being most widely adopted of their engines. However Id Tech 4 had far fewer licensees than the Unreal Engine from Epic Games, due to the long development time that went into Doom 3 which Id had to release before licensing out that engine to others.
In conjunction with his self-professed affinity for sharing source code, John Carmack has open-sourced most of the major Id Software engines under the General Public License. Historically, the source code for each engine has been released once the code base is 5 years old. Consequently, many home grown projects have sprung up porting the code to different platforms, cleaning up the source code, or providing major modifications to the core engine. Wolfenstein 3D, DOOM and Quake engine ports are ubiquitous to nearly all platforms capable of running games, such as hand-held PCs, iPods, the PSP, the Nintendo DS and more. Impressive core modifications include DarkPlaces which adds stencil shadow volumes into the original Quake engine along with a more efficient network protocol. Another such project is ioquake3, which maintains a goal of cleaning up the source code, adding features and fixing bugs.
The GPL release of the Quake III engine's source code was moved from the end of 2004 to August 2005 as the engine was still being licensed to commercial customers who would otherwise be concerned over the sudden loss in value of their recent investment.
Id Software publicly stated they would not support the Wii console (possibly due to technical limitations), although they have since indicated that they may release titles on that platform (although it would be limited their games released during the 1990s).
Since Id Software revealed their engine Id Tech 5, they call their engines "Id Tech", followed by a version number. Older engines have retroactively been renamed to fit this scheme, with the Doom engine as Id Tech 1.
Linux gaming 
Id Software was an early pioneer in the Linux gaming market, and Id Software's Linux games have been some of the most popular of the platform. Many Id Software games won the Readers' and Editors' Choice awards of Linux Journal. Some Id Software titles ported to Linux are Doom (the first Id Software game to be ported), Quake, Quake II, Quake III Arena, Return to Castle Wolfenstein, Wolfenstein: Enemy Territory, Doom 3, Quake 4, and Enemy Territory: Quake Wars. Since Id Software and some of its licencees released the source code for some of their previous games, several games which were not ported (such as Wolfenstein 3D, Spear of Destiny, Heretic, Hexen, Hexen II, and Strife) can run on Linux and other operating systems through the use of source ports.
The tradition of porting to Linux was first started by Dave D. Taylor with David Kirsch doing some later porting. Since Quake III Arena Linux porting has been handled by Timothee Besset. The majority of all Id Tech 4 games, including those made by other developers, have a Linux client available, the only current exceptions being Wolfenstein and Brink. Similarly, almost all of the games utilizing the Id tech 2 engine have Linux ports, the only exceptions being those created by Ion Storm. Despite fears by the Linux gaming community that Id Tech 5 would not be ported to that platform, Timothee Besset in his blog has stated "I'll be damned if we don't find the time to get Linux builds done". Besset has stated that Id Software's primary justification for releasing Linux builds is better code quality, along with a technical interest for the platform.
John Carmack has expressed his stance with regard to Linux builds in the past. Todd Hollenshead has also expressed support for Linux: "All said, we will continue to be a leading supporter of the Linux platform because we believe it is a technically sound OS and is the OS of choice for many server ops." However Carmack revealed that "there are no plans for a native Linux client" of id's most recent game, Rage.
Commander Keen 
The Commander Keen series, a platform game introducing one of the first smooth side-scrolling game engines for MS-DOS, brought Id Software into the gaming mainstream. The game was very successful and spawned a whole series of titles. It was also the series of Id Software that designer Tom Hall was most affiliated with.
The company's breakout product was 1992's Wolfenstein 3D, a first person shooter (FPS) with smooth 3D graphics that were unprecedented in computer games, and with violent gameplay that many gamers found engaging. After essentially founding an entire genre with this game, Id Software created Doom, Doom II, Quake, Quake II, Quake III Arena, Quake 4 and Doom 3. Each of these first person shooters featured progressively higher levels of graphical technology. Wolfenstein 3D spawned a prequel and a sequel, the prequel called Spear of Destiny, and the second, Return to Castle Wolfenstein, used the Id Tech 3 engine. A third Wolfenstein sequel, simply titled Wolfenstein, has been released by Raven Software, using the Id tech 4 engine.
Eighteen months after their release of Wolfenstein 3D, in 1993 Id Software released Doom which would again set new standards for graphic quality and graphic violence in computer gaming. Doom featured a sci-fi/horror setting with graphic quality that had never been seen on personal computers or even video game consoles. Doom became a cultural phenomenon and its violent theme would eventually launch a new wave of criticism decrying the dangers of violence in video games. Doom was ported to numerous platforms, inspired many knock-offs and was eventually followed by the technically similar Doom II. Id Software made its mark in video game history with the shareware release of Doom, and eventually revisited the theme of this game in 2004 with their release of Doom 3. John Carmack said in an interview at QuakeCon 2007 that there will be a Doom 4, it has been in development since May 7, 2008.
On June 22, 1996, the release of Quake marked the second milestone in Id Software history. Quake combined a cutting edge fully 3D engine with a distinctive art style to create critically acclaimed graphics for its time. Audio was not neglected either, having recruited Nine Inch Nails frontman Trent Reznor to facilitate unique sound-effects and ambient music for the game. (A small homage was paid to Nine Inch Nails in the form of the band's logo appearing on an ammunition box.) It also included the work of Michael Abrash. Furthermore, Quake's main innovation—the capability to play a deathmatch (competitive gameplay between living opponents instead of against computer-run characters) over the Internet (especially through the add-on QuakeWorld) seared the title into the minds of gamers as another smash hit.
In 2008, Id Software was honored at the 59th Annual Technology & Engineering Emmy Awards for the pioneering work Quake represented in user modifiable games. Id Software is the only game development company ever honored twice by the National Academy of Television Arts & Sciences, having been given an Emmy Award in 2007 for creation of the 3D technology that underlies modern shooter video games.
The Quake series continued with Quake II in 1997. However, the game is not a storyline sequel, and instead focuses on an assault on an alien planet, Stroggos, in retaliation for Strogg attacks on Earth. Most of the subsequent entries in the Quake franchise follow this storyline. Quake III Arena (1999), the next title in the series, has minimal plot, but centers around the "Arena Eternal", a gladiatorial setting created by an alien race known as the Vadrigar and populated by combatants plucked from various points in time and space. Among these combatants are some characters either drawn from or based on those in Doom ("Doomguy"), Quake (Ranger, Wrack) and Quake II (Bitterman, Tank Jr., Grunt, Stripe). Quake IV (2005) picks up where Quake II left off — finishing the war between the humans and Strogg. The spin-off Enemy Territory: Quake Wars acts as a prequel to Quake II, when the Strogg first invade Earth. It should be noted that Quake IV and Enemy Territory: Quake Wars were made by outside developers and not Id.
There have also been a few other spin off games such as Quake Mobile in 2005 and Quake Live, an internet browser based modification of Quake III. A game called Quake Arena DS is planned for the Nintendo DS. John Carmack stated, at QuakeCon 2007, that the Id Tech 5 engine would be used for a new Quake game.
Todd Hollenshead announced in May 2007 that Id Software had begun working on an all new series that would be using a new engine that is currently being developed by John Carmack. Hollenshead also mentioned that the title would be completely developed in-house, marking the first game since 2004's Doom 3 to be done so. At 2007's WWDC, John Carmack showed the new engine called Id Tech 5. Later that year, at QuakeCon 2007, the title of the new game was revealed as Rage.
On July 14, 2008, Id Software announced at the 2008 E3 event that they would be publishing Rage through Electronic Arts, and not Id's longtime publisher Activision. However, since then Zenimax has also announced that they are publishing Rage through Bethesda Softworks.
On August 12, 2010, during Quakecon 2010, Id Software announced Rage US ship date of September 13, 2011, and a European ship date of September 15, 2011. During the keynote, Id also demonstrated a Rage spin-off title running on the iPhone. This technology demo later became Rage HD.
Other games 
During its early days, Id Software produced much more varied games; these include the early 3D first person shooter experiments that led to Wolfenstein 3D and Doom — Hovertank 3D and Catacomb 3D. There was also the Rescue Rover series, which had two games — Rescue Rover and Rescue Rover 2. Also there was John Romero's Dangerous Dave series, which included such notables as the tech demo (In Copyright Infringement) which led to the Commander Keen engine, and the decently popular Dangerous Dave in the Haunted Mansion. In the Haunted Mansion was powered by the same engine as the earlier Id Software game Shadow Knights, which was one of the several games written by Id Software to fulfill their contractual obligation to produce games for Softdisk, where the Id Software founders formerly were employed. Id Software has also overseen several games using its technology that were not made in one of their IPs such as Shadowcaster, (early-Id Tech 1), Heretic, Hexen (Id Tech 1), Hexen II (Quake engine), and Orcs and Elves (Doom RPG engine).
Games developed by Id 
- Dangerous Dave (1988)[nb 1]
- Commander Keen
- Episode 1: Marooned on Mars (1990)
- Episode 2: The Earth Explodes (1991)
- Episode 3: Keen Must Die (1991)
- Keen Dreams (1991)
- Episode 4: Secret of the Oracle (1991)
- Episode 5: The Armageddon Machine (1991)
- Episode 6: Aliens Ate My Baby Sitter (1991)
- Dangerous Dave in the Haunted Mansion (1991)
- Rescue Rover (1991)
- Rescue Rover 2 (1991)
- Shadow Knights (1991)
- Hovertank 3D (1991)
- Catacomb 3D: A New Dimension (1991)[nb 2]
- Wolfenstein 3D (1992)
- Spear of Destiny (1992)
- Doom (1993)
- Doom II: Hell on Earth (1994)
- Quake (1996)
- Id Anthology (1996)[nb 3]
- Quake II (1997)
- Quake III Arena (1999)
- Quake III: Team Arena (2000)
- Doom: Collector's Edition (2001)
- Doom 3 (2004)
- Wolfenstein 3D Classic (2009)
- Doom Classic (2009)
- Quake Live (2010)
- Rage HD (2010)
- Rage (2011)
- Doom 3: BFG Edition (2012)
- Doom 4 (TBA)
Games by external developers 
- Heretic — Raven Software (1994)
- Hexen — Raven Software (1995)
- Doom 64 — Midway Games (1997)
- Hexen II — Raven Software (1997)
- Towers of Darkness: Heretic, Hexen & Beyond[nb 4] (1997)
- Quake expansion packs
- Quake II expansion packs
- Return to Castle Wolfenstein — Gray Matter Interactive, Nerve Software (multiplayer) (2001)
- Wolfenstein: Enemy Territory — Splash Damage (2003)
- Doom 3: Resurrection of Evil — Nerve Software (2005)
- Quake 4 — Raven Software (2005)
- Doom RPG — Fountainhead Entertainment (2005)
- Orcs & Elves — Fountainhead Entertainment (2006)
- Enemy Territory: Quake Wars — Splash Damage (2007)
- Wolfenstein RPG — Electronic Arts (2008)
- Doom Resurrection — Escalation Studios (2009)
- Wolfenstein — Raven Software (2009)
Other media 
Id Software has also been associated with novels since the publication of the original Doom novels. This has been restarted from 2008 onward with Matthew J. Costello's (a story consultant for Doom 3 and now Rage) new Doom 3 novels: Worlds on Fire and Maelstrom.
Id Software became involved in film development when they were in the production team of the film adaption of their Doom franchise in 2005. In August 2007, Todd Hollenshead stated at QuakeCon 2007 that a Return to Castle Wolfenstein movie is in development which re-teams the Silent Hill writer/producer team, Roger Avary as writer and director and Samuel Hadida as producer.
Doom was and remains notorious for its high levels of violence, gore, and satanic imagery, which have generated much controversy from a broad range of groups. Yahoo! Games has it listed as one of the top ten controversial games of all time. It has been criticized numerous times by religious organizations for its diabolic undertones and was dubbed a "mass murder simulator" by critic and Killology Research Group founder David Grossman. Doom prompted fears that the then-emerging virtual reality technology could be used to simulate extremely realistic killing, and in 1994 led to unsuccessful attempts by Washington state senator Phil Talmadge to introduce compulsory licensing of VR use.
The game again sparked controversy throughout a period of school shootings in the United States when it was found that Eric Harris and Dylan Klebold, who committed the Columbine High School massacre in 1999, were avid players of the game. While planning for the massacre, Harris said that the killing would be "like fucking Doom" and that his shotgun was "straight out of the game". A rumor spread afterwards that Harris had designed Doom levels that looked like the halls of the high school, populated with representations of Harris's classmates and teachers, and that Harris practiced for his role in the shootings by playing these levels over and over. Although Harris did design Doom levels, they were not simulations of Columbine High School.
Wolfenstein 3D 
As for Wolfenstein 3D, due to its use of Nazi symbols such as the Swastika and the anthem of the Nazi Party, Horst-Wessel-Lied, as theme music, the PC version of the game was withdrawn from circulation in Germany in 1994, following a verdict by the Amtsgericht München on January 25, 1994. Despite the fact that Nazis are portrayed as the enemy in Wolfenstein, the use of those symbols is a federal offense in Germany unless certain circumstances apply. Similarly, the Atari Jaguar version was confiscated following a verdict by the Amtsgericht Berlin Tiergarten on December 7, 1994.
Due to concerns from Nintendo of America, the Super NES version was modified to not include any swastikas or Nazi references; furthermore, blood was replaced with sweat to make the game seem less violent, and the attack dogs in the game were replaced by giant mutant rats. Employees of Id Software are quoted in The Official DOOM Player Guide about the reaction to Wolfenstein, claiming it to be ironic that it was morally acceptable to shoot people and rats, but not dogs. Two new weapons were added as well. The Super NES version was not as successful as the PC version.
In 2003, the book Masters of Doom chronicled the development of Id Software, concentrating on the personalities and interaction of John Carmack and John Romero. Below are the key people involved with Id's success.
John Carmack 
The lead programmer for Id Software is John Carmack, whose skill at 3D programming is widely recognized in the software industry. He is the last of the original founders still employed by the company.
John Romero 
John Romero, who was forced to resign after the release of Quake, later formed the ill-fated company Ion Storm. There, he became infamous through the development of Daikatana, which received generally negative reception from reviewers and gamers alike upon release.
Both Tom Hall and John Romero have reputations as designers and idea men who have helped shape some of the key PC gaming titles of the 1990s.
Tom Hall 
Tom Hall was forced to resign by Id Software during the early days of Doom development, but not before he had some impact; he was responsible, for example, for the inclusion of teleporters in the game. He was let go before the shareware release of Doom and then went to work for Apogee, developing Rise of the Triad with the "Developers of Incredible Power". When he finished work on that game, he found he was not compatible with the Prey development team at Apogee, and therefore left to join his ex-Id compatriot John Romero at Ion Storm. Hall has frequently commented that if he could obtain the rights to Commander Keen, he would immediately develop another Keen title.
Sandy Petersen 
Sandy Petersen was a level designer for 19 of the 27 levels in the original Doom title as well as 17 of the 32 levels of Doom II. As a fan of H.P. Lovecraft, his influence is apparent in the Lovecraftian feel of the monsters for Quake, and he created the fourth and final "episode" of the game. He left Id Software during the production of Quake II and most of his work was scrapped before the title was released.
American McGee 
American McGee was a level designer for Doom II, The Ultimate Doom, Quake, and Quake II. He was asked to resign after the release of Quake II, then moved to Electronic Arts where he gained industry notoriety with the development of his own game American McGee's Alice. After leaving Electronic Arts, he became an independent entrepreneur and game developer. McGee now heads independent development house Spicy Horse in Shanghai, where he works on various projects.
- Kushner, David (2003). Masters of Doom: How Two Guys Created an Empire and Transformed Pop Culture, New York: Random House. ISBN 0-375-50524-5.
- Dangerous Dave is a solo project of John Romero predating Id's formation, but Id Software produced its first sequel and it is sometimes regarded as an early Id Software title. Later Dangerous Dave sequels were not made by Id, nor were later Catacomb titles.
- Re-released as Catacomb 3-D: The Descent.
- Id Anthology is a compilation consisting of all of Id Software's games, with the exception of the Heretic and Hexen series. Since only 10,000 copies were made, this compilation is often sought by collectors.
- Towers of Darkness: Heretic, Hexen & Beyond is a compilation containing Heretic: Shadow of the Serpent Riders, Hexen and Hexen: Deathkings of the Dark Citadel.
- Quake: The Offering is a compilation containing the original Quake and the two official expansion packs.
- Quake II: Quad Damage is a compilation containing Quake II, the two official expansion packs and Quake II Netpack I: Extremities.
- August 4th, 2011 (2011-08-05). "QuakeCon 2011 Carmack's Keynote". youtube. Retrieved 2011-08-06.
- Burney, Nabeel; Wilbur, Jay (2011-01-24). "Interview with Epic Games' Jay Wilbur". Slowdown. Retrieved 2011-04-04.For the same-named British bandleader, see Jay Wilbur (1898-1970).
- "Interview with John Romero". 2006-05-15. Retrieved 2010-07-12.
- "20 Years of Evolution: Scott Miller and 3D Realms". 2009-08-21. Retrieved 2010-07-12.
- Remo, Chris (2009-06-24). "Bethesda Parent ZeniMax Acquires Id Software". Gamasutra. Retrieved 2009-06-24.
- "Id's History page". Idsoftware.com. Retrieved 2010-10-25.
- Kushner, David (2004). Masters of Doom (paperback ed.). Random House Publishing Group. pp. 119–122. ISBN 0-8129-7215-5.
- "Doom 3 Source-Code To Be Released This Year".
- "Id Software boss unconvinced by Wii". 2009-04-12.
- "Id Properties Coming to Wii" from Cubed3
- "Id Software: Technology licensing". idsoftware.com. Archived from the original on 2007-12-15. Retrieved 2007-07-15.
- HEXUS.gaming - Feature - Linux Gaming Jo Shields, March 25, 2005
- 1997 Readers' Choice Awards Linux Journal, December 1997
- 2000 Readers' Choice Awards Linux Journal, November 2000
- Linux Journal Announces Winners of 8th Annual Readers' Choice Awards Linux Journal, October 2002
- Editors' Choice 2006 Linux Journal, November 2006
- Bad news. Id Software really is abandoning Linux. - Ubuntu Forums. Retrieved 2009-09-16.
- "Id Software and Linux - TTimo's blog". Ttimo.vox.com. Retrieved 2010-10-25.
- "id on Linux: "disappointing" and "support nightmar" from Slashdot
- Id Software on Linux: "disappointing" and "support nightmare from Slashdot
- Carmack, John. "Twitter / @ID_AA_Carmack: @joedaviso I heard it ran...".
- "QuakeCon 2007: John Carmack Talks Rage, Id Tech 5 And More". Web.archive.org. Archived from the original on 2007-10-29. Retrieved 2010-10-25.
- 2008 Tech Emmy Winners from Kotaku.com
- "John Carmack and Id Software's pioneering development work in 3d games recognized with two Technology Emmy Awards" from Shacknews
- "New IP Coming From Id Software". Totalgaming.net. 2007-05-31. Archived from the original on 2007-09-27. Retrieved 2007-06-01.
- "WWDC: Game On". MacRumors. 2007-06-11. Retrieved 2007-06-11.
- "Id Reveals Rage, Implies PS3, 360 and PC Versions". shacknews. 2007-08-03. Retrieved 2007-08-03.
- "Id Software, EA Partner For RAGE Publishing Deal".
- "Zenimax/Bethesda to publish RAGE".
- "Id shows more Rage and announces release date".
- "QuakeCon: Rage coming to iPhone, running at 60fps". from Joystiq.com
- Ultimate Doom article at the Doom Wiki
- Announcement of Wolfenstein 3D Classic from official Id home page
- Announcement of Doom Classic progress from official Id home page
-  from official Id home page
- Announcement of Doom 4 from official Id home page
- "Towers of Darkness: Heretic, Hexen & Beyond for DOS". MobyGames. Retrieved 2010-10-25.
- "Quake: The Offering". MobyGames. Retrieved 2010-10-25.
- "Quake II: Quad Damage for Windows". MobyGames. 1998-09-30. Retrieved 2010-10-25.