Brutal warfare has been a constant companion of mankind. Sometimes rulers launch wars of aggression and those being attacked must defend themselves. At other times rival groups seem to go to war as a matter of course over wealth, religious differences, territory, or food supplies - or simply because they don’t like each other much.Innovative use of even simple technology can trump weight of numbers.Superior technology can facilitate aggression or enable besieged societies to defend themselves. It can prevent conflict altogether.We look at the startling impact an innovation in weapon systems can have and be astonished. We look at times when innovative technology was available but not used, and shake our heads in disbelief. Today, when innovation is critically important, history has much to teach us.