The Dark Templar Saga is a trilogy of books written by author Christie Golden. It details events in protoss history and serves as a prequel to StarCraft II storyline, setting up some plotlines and foreshadowing some of its events. It was written concurrently with StarCraft II's storyline. The Dark Templar Saga was originally said to take place in the fourth year after the Brood War, putting it many months or a year before StarCraft II. However, the timeline in StarCraft II: Heaven's Devils lists it as occurring in 2503. In regards to links to timeline articles, this wiki has gone with the '03 timeframe.
Christie Golden described the first novel, Firstborn, as "kind of a thriller/action/mystery" novel and "Bladerunner meets Indiana Jones".