Sid Meier's Alpha Centauri (SMAC) is the critically acclaimed science fiction 4X turn-based strategy video game sequel to the Civilization series. Sid Meier, designer of Civilization, and Brian Reynolds, designer of Civilization II, developed Alpha Centauri after they left MicroProse to join the newly-created developer Firaxis Games. Electronic Arts released both SMAC and its expansion, Sid Meier's Alien Crossfire (SMAX), in 1999.