Pr0n K1ng seems to have noded the good part of Looking Glass' history so I'm going to continue with the bad part.
The bad part is the Looking Glass is no more. It was shutdown just after Thief 2 was ready. This is a tremendous loss for all gaming. The big question is WHY? Looking Glass was making great "artistic" games and the games even sold pretty well at the same time their producer, Eidos, funded John Romero and Co. with Daikatana which is mostly considered as a bad, normal first-person shooter. So it goes.
The theory that I belive, is that Looking Glass was shutdown because Eidos had lost a lot of money with Daikatana and knew that the money was not coming back. So they had to choose from Looking Glass or John Romero. And because John Romero is John Romero he had to stay. So they fired Looking Glass. This is how great decision are made.
The odd part is that Eidos that quarter's revenues were mostly generated by Thief 2, not by Daikatana. John Romero didn't make you his bitch... Thank God for that atleast.
Well I guess this is more of the good part - Now most of the people of Looking Glass are working with Ion Storm and busy making Thief 3. So I guess this story has an ending, but is the ending good or what? I guess we'll see when Thief 3 is out and installed on our machines.
PS. John Romero was fired a couple of days ago. Very sad.