The Gamma Quadrant Sourcebook provides Gamemasters and Players with a wealth of information to aid in playing characters or running adventures set within the ever-expanding Star Trek universe. The Gamma Quadrant Sourcebook contains: Information on the Federation's relationship with the Dominion and other Gamma Quadrant denizens, as of 2375. Material about the Dominion and its history, structure, and culture; including information on many of its member worlds, allies, and enemies. Detailed information about the brutal Dominion War, from its beginnings as a cold war to open conflict involving billions of beings. A dozen new alien species to choose from during character creation, including the Dosi, Lurians, S'ona, Wadi, and the Changelings! A selection of starships from the Dominion and S'ona, as well as several notable wartime Federation vessels. Guidance for the Gamemaster on running missions and continuing voyages in the Gamma Quadrant and on the front line, along with a selection of new Non-Player Characters to enhance encounters.