This chapter starts by delimiting the scope of the book and making clear that we focus on various types of domestic political violence but that international wars are touched upon as well. We clearly define these terms and provide examples that illustrate the differences between distinct forms of violence, before moving to a discussion of the costs that these forms of violence impose on society. Strikingly, some people believe that wars and conflicts are good business. They are not. This chapter shows that wars not only destroy millions of innocent lives, but they are also poison for the economy. In particular, wars may be lucrative for the few but disastrous for the many. The detriments of war are manifold and include human, economic and social costs. This is illustrated by a series of historical examples. Drawing on recent cost estimates, it is also shown that the costs of a given war spread well beyond the borders of the country at war, with continental if not worldwide consequences.