SAARC to BIMSTEC: Breakdown or Breakthrough in Regional Co­operation? explores the persistent challenges and evolving possibilities of regionalism in South Asia. Tracing the trajectory from SAARC’s founding vision to the emergence of BIMSTEC, the book examines why regional cooperation in this part of the world has remained elusive despite shared geography, history, and development goals. At its core, the work identifies three structural impediments that continue to undermine meaningful collaboration: the absence of a clear political mandate from member states, the limitations of the SAARC Secretariat, and the exclusion of civil society from the regional process. Without addressing these foundational issues, neither SAARC nor BIMSTEC can effectively reconcile national priorities with the broader regional good. Set against the shifting dynamics of the Indo-Pacific, this study highlights how time, technology, and global competition have intensified both the risks and opportunities confronting South and Trans-Himalayan Asia. It calls for a renewed vision of regional cooperation – one that moves beyond political posturing toward a more balanced framework of shared governance and collective progress.