McFate demonstrates a lively and provocative way to think about modern warfare in a book laced with examples from the history of conflict as well as his own career as a soldier in the U.S. Army and a professor at Georgetown University’s School of Foreign Service. His starkest argument is that “conventional war is dead,” while lesser war and peace exist side by side, and that much great-power conflict takes place in a gray zone between the two. McFate does a good job conveying the messiness of contemporary warfare, describing a shift from wars between states to wars within states. Great powers pursue their interests by using whatever nonmilitary tools are available, from social media to trade, and try to avoid serious fighting. Nonstate actors, on the other hand, use whatever weapons they can get their hands on. At times, McFate overstates for effect. For example, he dismisses high-end conventional capabilities too readily: along with nuclear weapons, such military options—even when they are not used—help explain why great powers are wary about embarking on major wars.