How states cooperate in the absence of a sovereign power is a perennial question in international relations. With Power in Concert, Jennifer Mitzen argues that global governance is more than just the cooperation of states under anarchy: it is the formation and maintenance of collective intentions, or joint commitments among states to address problems together. The key mechanism through which these intentions are sustained is face-to-face diplomacy, which keeps states' obligations to one another salient and helps them solve problems on a day-to-day basis. Mitzen argues that the origins of this practice lie in the Concert of Europe, an informal agreement among five European states in the wake of the Napoleonic wars to reduce the possibility of recurrence. The Concert first institutionalized the practice of jointly managing the balance of power, through its many successes, and Mitzen shows that the words and actions of state leaders in public forums contributed to collective self-restraint and a shared commitment to problem solving-and at a time when communication was considerably more difficult than it is today. Despite the Concert's eventual breakdown, the practice it introduced-of face-to-face diplomacy as a mode of joint problem solving-survived and is the basis of global governance today.