Id Software LLC (/ɪd/, 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 theWolfenstein 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.

History
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).

Id Software has moved from the "cube-shaped" Mesquite office, to a newly built location in Richardson, Texas.

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 bySigmund 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.