Reign of Steel is a setting sourcebook for the GURPS role-playing game system describing a future world conquered by a conspiracy of artificial intelligences. It is written by David Pulver, who also wrote the Robots, Ultra-Tech and Vehicles sourcebooks - all of which are strongly recommended to get full use of this setting, though they are not required. The Reign of Steel setting starts in the year 2047 AD, 16 years after the robot revolt has concluded with the machines' victory.