The Dueling Machine by Ben Bova is the solution to settling disputes without injury. After you and your opponent select weapons and environments you are injected into an artificial reality where you fight to the virtual death… but no one actually gets hurt. That is, until a warrior from the Kerak Empire figures a way to execute real-world killings from within the machine. Now its inventor Dr. Leoh has to prevent his machine from becoming a tool of conquest. – The Dueling Machine, written with Myron R. Lewis, first appeared in the May, 1963 issue of Analog Science Fact & Fiction.