Valve is an entertainment software and technology company founded in 1996 by former Microsoft employees Gabe Newell and Mike Harrington. Based in Bellevue, Washington, the company first became famous with the 1998 release of its debut title, Half-Life, which has received worldwide critical acclaim.
Valve soon expanded the Half-Life franchise with a sequel and Half-Life 2 Episodes 1 and 2. New games were also released such as zombie shooters Left 4 Dead and Left 4 Dead 2, the multiplayer combat franchise Team Fortress 2, the #1 online action game Counter-Strike and the award-winning puzzlers Portal and Portal 2.

In addition to producing best selling entertainment titles, Valve is a developer of leading-edge technologies including Steam. Steam has quickly become the world's largest online gaming platform. Steam guarantees instant access to more than 1,800 game titles and connects its 35 million active users to each other with community features. Through Steam, fans can easily buy, play, share, modify, and build communities around Valve products as well as titles from other independent game studios.

In addition to Steam, there is Source, their custom built game engine which all their games since Half-Life 2 have taken advantage of. Its sophisticated character animation, advanced AI, real-world physics, shader-based rendering, and super extensibility have made it one of the most flexible, comprehensive, and powerful game development environments available.

1996 Gabe and Mike Harrington fly to Texas to meet with id software. August 24th, Mike Harrington and Gabe Newell form Valve Software. Company documents are signed on Gabe Newells wedding day. August 26th, Team Fortress is released as a Quake mod.       1997 May 27th, Sierra announces plans to publish Half-Life. June 19th-21st, Half-Life is demonstrated at E3 trade show. October 2nd, Half-Life delay is officially announced. First quarter 1998 release date is set. Half-Life is scrapped and restarted. October 16th, Half-Life Preliminary Findings CD released to select retail outlets containing early Half-Life media.       1998 Prospero development is shelved. May 24th, First Half-Life ads appear in the gaming press. June 1st, Half-Life is shown in its new form at the E3 trade show. June 30th, Sierra pushes back the release date to 'fall 1998'. Valve denies the rumour stating a "summer" release is still occurring. September 9th, Official letters reveal release date to be October 15th. Official press release details the shipping of Day One OEM Half-Life. September 28th, Sierra representative confirms new release date of "late October" after rumour of a November 7th completion. November 9th - Half-Life goes gold. November 19th, Half-Life is released.       1999 January 13th, Team Fortress Classic is announced as a free ad-on available "in the coming weeks". February 12th, The Uplink Demo is released with an all-new adventure designed to interest new users becomes available. March 15th, Gooseman and Cliffe start development of Counter-Strike. April 7th, Team Fortress Classic is released. April 7th-9th, The SDK is officially released. April 16th, Opposing Force is announced as a retail add-on for Half-Life. July 29th-August 3rd, The first Mod Makers exhibition is declared a success. May, Opposing Force is showcased at E3 trade event. October 19th, Half-Life for Mac is cancelled. June 19th, The first version of the Counter-Strike Half-Life modification is released in beta. June 25th, Half-Life Game of the Year Edition is released with Team Fortress classic included. November 10th, Half-Life: Opposing Force is released. December 19th, Half-Life Adrenaline Pack is released with the original game, TFC and Opposing Force.       2000 August 29th, Joint press release regarding Dreamcast Half-Life incorporating Blue Shift. November 1st, Valve release Ricochet as a free Half-Life add-on. November 9th, Half-Life platinum pack is released. November 20th, Gunman Chronicles is released. November 20th, The Counter-Strike mod ream partner with Valve and release a polished retail version of the game.       2001 Counter-Strike is adopted as the feature event at gaming tournaments worldwide such as the World Cyber Games and others. March 16th, Dreamcast Half-Life with Blue Shift is cancelled. Work begins on a single-player version of Counter-Strike later transformed into Condition Zero and Counter-Strike Xbox. June 1st, Deathmatch Classic is released. June 12th, Half-Life: Blue Shift is released on PC. November 12th, Half-Life on the Playstation 2 with Decay is released.       2002 March 22nd, Valve announce plans for Steam at the Games Developer Conference. June, Day of Defeat team offered a job at Valve June 12th, Richochet is released.       2003 March 21st, Valve internally schedule Half-Life 2's release for 'September 30th' a date which is infamous with HL2 fans. April 4th, Day of Defeat goes gold. April 21st, First media reports on Half-Life 2 are shown. May 1st, Day of Defeat released as a retail game. May, Half-Life 2 first shown at E3 trade show. Release date is set for September 30th. September 11th, Signs of odd computer happenings at Valve begin. September 19th, An unknown person makes a copy of the Half-Life 2 source tree. And key loggers are believed to have been installed on Valve computer systems. September 30th, Half-Life 2 fails to ship. October 2nd, The infamous "I need the assistance of the community" forum thread by Gabe Newell announcing the theft of the Half-Life 2 source code. November 18th, Counter-Strike on the Xbox is released.       2004 March 21, Counter-Strike: Condition Zero is released as a retail game. May, Half-Life 2 is shown (twice) at E3 trade show. June 10th, Persons responsible for Source code theft are arrested. Summer, Counter-Strike: Source is announced at E3 trade show. June 1st, Valve release Half-Life: Source - a port of Half-Life to the new Source engine but with all the old textures intact. October 7th, Valve release Counter-Strike: Source in beta. November 16, Valve release Half-Life 2. November 30th, Valve release Half Life 2: Deathmatch.       2005 July 2nd, Valve release Half-Life Deathmatch: Source. September 28th, Day of Defeat: Source, a rebooted version of the Day of Defeat HL mod is released in retail stores using the new Source engine. October 27th, Half-Life 2: Lost Coast released.       2006 June 1st, Half-Life 2: Episode One is released.       2007 October 9th, Valve release Team Fortress 2, Portal and Half-Life 2: Episode Two and bundle them all together in "The Orange Box". December 22nd, The Orange Box soundtrack released.       2008 January 22nd, Valve announce Team Fortress 2 to get unlockable weapons and class changes - the start of major TF2 community development. January 29th, Valve releases Steamworks, a complete suite of publishing and development tools. April 1st, Portal credits song "Still Alive" made available on Rock Band a music game for the Xbox 360. May 30th, Valve announces Steamcloud, a cloud computing file share that can automatically store game saves and related custom files to Valve's services. October 30th, Valve launch TV adverts for Left 4 Dead. November 21st, Left 4 Dead is released.       2009 November 17th, Left 4 Dead 2 is released.       2010 January 10th, Valve acquires Turtle Rock studios. March 16th, Valve release Steam Guard, a new feature of Steam which protects users accounts from being hijacked. July 19th, Valve release Alien Swarm, a remake of the original mod for Unreal Tournament 2004. August 9th, Blizzard filed an opposing trademark, to protect the DOTA name from Valve. October 13th, Valve announce the development of DOTA 2. A standalone sequel to the popular Defence of the Ancients mod for Warcraft 3.       2011 April 19th, Portal 2 is released. November 10th, Valve announce that one of their Steam customer databases had been hacked into and the hackers potentially had access to customer records and credit card numbers.       2012 January 24th, Valve games now available on digital distribution service Impulse. January 31st, Valve officially launch a new Android and iOS version of their Steam client. February 14th, A new range of Valve game characters in action figure format are revealed at the NECA booth at the 2012 toy fair. February 15th, Valve launches Counter-Strike: Global Offensive website.