Since 3500 BC, it has been claimed, around 14,500 wars have been fought. Humanity has enjoyed only 300 years of peace on earth. But are we gradually becoming more peaceful? During the 20th century, the absolute number of people killed in wars was greater than in any previous century. In relative terms, however, we may be killing each other less often. Whatever the quantities of the dead, however, and whatever technology is being deployed, we can be sure that \Vars will continue to be fought. Do the origins of war lie in society or biology, in competition for economic resources or sexual ones, in historical circumstances - or in a universal instinct for violence? Based on the Engelsberg setninar of 2015, the essays in this anthology have been produced by an international forum of historians, journalists, thinkers, researchers and authors. From the conflicts of antiquity to the dynamics of modern terrorism, they deal with war as creator and destroyer of states and civilisations.