The Thief series has a strong heritage, and a long and important history on the PC, effectively creating the stealth genre single-handedly. The first Thief game, The Dark Project was a ground-breaking title at the time, arriving as the FPS genre was really taking off, and quite possibly being somewhat overlooked due to its lack of "run-and-gun" gameplay that was all the rage those days. Looking Glass Studios (lamentably a dead development house) had a reputation for releasing amazing games - lauded with critical acclaim, and largely disregarded by consumers. Some excellent titles from their library include Terra Nova: Strike Force Centauri and, many people's all-time favorite, System Shock. The games they created never fit neatly into a genre, or else they created one unto themselves. Terra Nova was essentially a tactical squad-based shooter long before Rainbow 6 was even an idea, and System Shock was largely a survival horror game with a first person perspective and RPG elements (talk about genre-busting!). This is a lofty lineage to live up to, with a vocal and sometimes-vehement fan base, and woe to the developer who attempts to pick up where the Thief series left off should they irk their public in some way.