Carl L. Sargent (born December 11, 1952, in Caerleon, Monmouthshire) is a British game designer and psychologist who has written several role-playing game products and novels.
It is also believed that he wrote Fighting Fantasy gamebooks under the pseudonym Keith Martin and Sonic the Hedgehog novels under the collective pseudonym Martin Adams.
In 1979, he earned a PhD in psychology. His post-doctoral research was concerned with ESP and he has been widely regarded as an authority on the paranormal.