Zork I: The Great Underground Empire is an interactive fiction computer game written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson and published by Infocom in 1980. It was the first game in the popular Zork trilogy and was released for a wide range of computer systems, followed by Zork II and Zork III. Selling more than 400,000 copies, it is Infocom's first game.