A. Mark Ratner (born November 1948 in New Jersey) is an American game designer, author, former army veteran, engineer, and college professor who is known for working with the games Space Marines and Space Opera. He holds four engineering degrees including a PhD in civil engineering. In 1977, he founded FanTac Games which published three games: Space Marines, Giac My, and Orbit War.
Note: This appears to be different person than Mark A. Ratner (born 1942), a professor of science and engineering at Northwestern University.