It is known for its graphical adventure game series King's Quest, Space Quest, Police Quest, Gabriel Knight, Leisure Suit Larry, and Quest for Glory, and as the original publisher of Valve's Half-Life series.Īfter seventeen years as an independent company, Sierra was acquired by CUC International in February 1996 to become part of CUC Software. The company is known for pioneering the graphic adventure game genre, including the first such game, Mystery House. (formerly On-Line Systems and Sierra On-Line, Inc.) was an American video game developer and publisher founded in 1979 by Ken and Roberta Williams.
