Why do states choose to intervene covertly in a conflict, when more overt efforts are likely to be more successful? Even more puzzling, why do states sometimes treat covert interventions as ‘open secrets,’ where states—even enemies—decide not to recognize the intervention, even when it is common knowledge? These are the critical questions Austin Carson poses in his outstanding book, Secret Wars. The answer, he argues, lies in fears of escalation. On the one hand, by intervening covertly, a state hopes to reduce the risk of escalation by keeping the intervention out of sight from hawkish publics, actors at home that might push for increased offensive action, even at the risk of catastrophic war. On the other hand, a covert intervention can be read as a sign by other states that the action will remain limited and, by keeping the intervention covert, ensure that more hawkish actors abroad will demand an escalatory response. Indeed, at times, major powers—even entrenched enemies like the United States and Soviet Union—will collude in order to keep the intervention a secret, and reduce the risk of war.