An acclaimed expert on violence and seasoned peacebuilder explains the five reasons why conflict (rarely) blooms into war, and how to interrupt that deadly process. It's easy to overlook the underlying strategic forces of war, to see it solely as a series of errors, accidents, and emotions gone awry. It's also easy to forget that war shouldn't happen-and most of the time it doesn't. Around the world there are millions of hostile rivalries, yet only a tiny fraction erupt into violence. Too many accounts of conflict forget this. With a counterintuitive approach, Blattman reminds us that most rivals loathe one another in peace. That's because war is too costly to fight.