In an era of complex global challenges, traditional state-to-state negotiations often fall short. Track 1.5 Diplomacy- combining official and unofficial dialogue- has become essential for building trust, fostering cooperation, and generating innovative solutions. This book offers the first in-depth study of Track 1.5 Diplomacy in the US and Europe, blending theory and practice. It examines how governments, think tanks, academics, and civil society collaborate in semi-official settings to i...