Is military power central in determining which states get their voice heard? Must states run a high risk of war to communicate credible intent? In this book, Slantchev shows that states can often obtain concessions without incurring higher risks when they use military threats. Unlike diplomatic forms of communication, physical military moves improve a state’s expected performance in war. If the opponent believes the threat, it will be more likely to back down. Military moves are also inherently costly, so only resolved states are willing to pay these costs. Slantchev argues that powerful states can secure better peaceful outcomes and lower the risk of war, but the likelihood of war depends on the extent to which a state is prepared to use military threats to deter challenges to peace and compel concessions without fighting. The price of peace may therefore be large: states invest in military forces that are both costly and unused.