The main concept behind Thief was to turn the first-person shooter idea on its head. Everyone plays first-person games with the idea of killing enemy after enemy in a Rambo style until bored or until the game is beaten. But Thief takes a different approach; the main tactic of the game is to avoid fights, and not to kill.
The game is sometimes described as either a First person sneaker or First-person looter to emphasize this difference.
Through careful use of sound effects and a very involving plot line, the player is drawn in to the milieu of the game.
Thief was originally published by Looking Glass Studios, which went out of business in 2001. The long-anticipated third game of the series is being done by developers at ION Storm Austin (the team includes many ex-Looking Glass employees) and will probably be published by Eidos Interactive.
See also: Steampunk, Taffer