As we approach the 21st century our fears are changing shape: no longer will nuclear holocaust hold sway in our minds as God's destruction by fire and brimstone did for our ancestors at the end of the first millennium. Refugees streaming north from the poverty-stricken south, destruction of the planet's life-preserving balance and the epidemic of AIDS nurture a more insidious dread that won't yield to the simple logic of deterrence. What then will have to be faced in future battles? Where will the lines of defence be drawn, and what will be left for the serving soldier to do?