This book provides fresh insight into multilateral diplomacy, revealing how informal cooperation—not just formal mechanisms —drives EU foreign policy success. Drawing on interviews with diplomats and analysis of critical cases, including sanctions against Russia and Ukraine response coordination, this groundbreaking study exposes the essential role of behind-the-scenes negotiations and informal coalitions.

From defence cooperation mechanisms like Permanent Structured Cooperation (PESCO) to the naval Operation Irini, the book demonstrates how informality compensates for institutional rigidity, enabling swift decision-making in crisis situations. It directly speaks to international relations scholars, diplomats and policymakers seeking to understand how global governance functions in practice.