Patrikarakos has gone to the frontlines of modern warfare to interview representatives of a species he calls Homo digitalis: individuals whose skill with social media allows them to reshape the conduct of contemporary conflicts. These include teenage Palestinian Twitter users who can convey the terror of living through Israeli bombardments of Gaza; a Ukrainian activist who uses Facebook to crowdsource funds and supplies for beleaguered Ukrainian forces fighting Russian-backed separatists; a former employee of a Russian “troll farm” who made up and spread false news; and Eliot Higgins, a former video-game obsessive who exposed Russian propaganda about the shooting down of a Malaysian civilian airliner over Ukraine in 2014. He also tells the story of officials, particularly in Israel and the United States, who have tried to match their opponents’ agility and ubiquity but have struggled to make government bureaucracies more responsive. This is a highly readable introduction to some big issues in contemporary war. Patrikarakos asks searching questions and never overstates his case. One idea emerges quite clearly, however: it remains difficult to win a narrative battle when losing a physical one.