Give me a history of Valve

Founding and Half-Life (1996–2003): Valve was founded as Valve, LLC, in 1996 by former Microsoft employees Gabe Newell and Mike Harrington in Kirkland, Washington. Valve's first game is Half-Life, a first-person shooter (FPS) released in November 1998. It was developed using the modified Quake engine GoldSrc. After struggling to find a publisher, Valve eventually signed with Sierra On-Line.