For much of recorded history, the most frequent, horrific, destructive and yet strangely overshadowed form of collective human violence has been civil war. It has shattered communities and scarred imaginations as much as it has shaped nations and staged pivotal moments in world history. Nor has such carnage been confined to the distant past: in the last fifty years almost half the world's countries, especially its poorest, have suffered civil war, with their impact being estimated at about $100 billion per annum, or roughly twice what is spent annually on aid to developing countries. Civil war is also big business. Economists, political scientists, aid agencies, development strategists and governments put major resources into examining the factors that cause civil war, what determines its intensity and duration, how civil wars end, and why they seem so often to recur. In other words it is a global scourge and one that shows no signs of disappearing any time soon.