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.