Diplomacy is essential to the conduct of foreign policy and international business in the twenty-first century. Yet, few international actors are trained to understand or practice effective diplomacy. Poor diplomacy has contributed to repeated setbacks for the United States and other major powers in the last decade. Drawing on deep historical research, this book aims to 'reinvent' diplomacy for our current era. The original and comparative research provides a foundation for thinking about what successful outreach, negotiation, and relationship-building with foreign actors should look like. Instead of focusing only on failures, as most studies do, this one interrogates success. The book provides a framework for defining successful diplomacy and implementing it in diverse contexts. Chapters analyze the activities of diverse diplomats (including state and non-state actors) in enduring cases, including: post-WWII relief, the rise of the non-aligned movement, the Nuclear Non-Proliferation Treaty, the U.S. opening to China, the Camp David Accords, the reunification of Germany, the creation of the European Union, the completion of the North American Free Trade Agreement, and relief aid to pre-2001 Afghanistan. The cases are diverse and historical, but they are written with an eye toward contemporary challenges and opportunities. The book closes with systematic reflections on how current diplomats can improve their activities abroad. Foreign Policy Breakthroughs offers rigorous historical insights for present policy.