Mark Leonard, director of the European Council on Foreign Relations, examines how the interconnection that was supposed to bring peace and prosperity has instead become a source of conflict and instability. The book argues that we have entered an 'age of unpeace' in which the very networks and dependencies created by globalization are being weaponized. China uses economic leverage to punish countries that displease it; Russia turns off natural gas pipelines to coerce neighbors; the United States deploys its control of the financial system to enforce sanctions; all parties engage in cyber operations that exploit digital interdependence. Leonard traces how the liberal assumption that economic integration would prevent conflict has been proven wrong, yet countries remain too interconnected to retreat into isolation. He examines specific cases including technology supply chains, migration flows, and pandemic response to show how connection has become a vulnerability. The book calls for new forms of international cooperation that acknowledge the dangers of interdependence while preserving its benefits, a delicate balance that requires moving beyond both naive globalism and reactive nationalism. Leonard writes with the urgency of someone who has watched the international order he helped build come under attack, while maintaining analytical distance that allows for clear-eyed assessment of what has gone wrong and what might be done.