'Help! I've been spotted!' Terry Pratchett on Thief, his favourite video game

In November 2001, Terry Pratchett was in Chester, famed for its Roman ruins and well-preserved medieval architecture. Staying at a hotel in the city centre, Pratchett opened the window of his room, and looked across the historic skyline. "I realised I could drop down on to a roof," he wrote later. "And from then on there was a vista of roofs, leads and ledges leading all the way to the end of the street and beyond; there were even little doors and inviting attic windows … There is a line break, and then he adds. "I'm going to have to stop playing this game." Pratchett was not considering a new career as a cat burglar. He was reflecting on his favourite video game – Thief II: The Metal Age. Released in March 2000, Thief II was the sequel to 1998's Thief: The Dark Project, a pioneering stealth game set in a gothic fantasy world. In both games, players donned the cowl of Garrett, a laconic master thief partly inspired by Raymond Chandler's PI Philip Marlowe. Thief charged players with breaking into medieval mansions, rooftop apartments, banks, cathedrals even police stations, stealing as much coin and valuables as they could while avoiding patrols of sword-wielding guards. Pratchett's relationship with video games is well documented. Always technologically savvy, he was an early adopter of PC gaming, and enjoyed everything from Doom to Deus Ex and Call of Duty. He even helped to create a mod (an unofficial add-on) for The Elder Scrolls IV: Oblivion, writing lines of dialogue for a character. But Pratchett held a particular affection for Thief. He played all three games in the series, and often contributed to a Usenet newsgroup named alt.games.thief-dark-project. That newsgroup, analogous to a modern forum, has long since been deactivated, but its posts survive in a Google groups archive. Combined, they provide a fascinating record of Pratchett's evolving relationship with both the Thief series and video games in general. Like so many players who become involved in online communities, he posted because he was stuck. In a post titled: "Help!