Today, great-power and middle-power diplomacy take place at two high tables, one using a well-known fixed address on First Avenue in Manhattan and the other at varying summit locations where heads of state and government meet. This book examines the growing importance of minilateral summit diplomacy in the management of international security problems. Kjell Engelbrekt contrasts the "GX" summitry of the G7 (formerly the G8) and G20 clubs with the older and more formal UN Security Council. He examines whether or not this new form of GX high-table diplomacy offers a more effective alternative to, or whether it simply complements, traditional institutions. One defining feature of GX diplomacy has been the diversification of countries with seat at the table, as seen by contrasting the G20 with the five-member UN Security Council. A second feature of GX summits are their relative informality and flexibility, which has helped put non-traditional security threats on the agenda. Engelbrekt conducted research in primary-source documents of the G7, G8, G20, and UN Security Council to examine and contrast how these institutions have deliberated on three policy areas: conflict management, counterterrorism cooperation, and climate change mitigation.