In the riverine valleys of the Pamir Mountains of Tajik Badakhshan, a thriving millennium-old community of Nizari Ismaili Muslims created a unique spiritual culture in which the performance of music and poetry plays a central role. This book focuses on the central musical and poetic tradition of the Pamiri Ismailis, qasda-khon (also known as maddo), tracing its origins, evolution, and eventual delocalization and relocation in new social contexts. The first study on the musical culture of the Pamiri Ismailis in almost 20 years, this monograph introduces readers to leading performers of qasda-khon and to the Ismaili gnosis that inspires its music and poetry-a foundational source for an understanding of Islam in Badakhshan as an amalgam of diverse cultural practices and multi-layered identities. In an era of cultural globalization, the circulation of qasda-khon and maddo beyond Badakhshan serves as a case study of global cultural flows, diversity, versatility, and connectedness.