Book excerpt: A group of ritual musicians and former slaves brought from sub-Saharan Africa to Morocco, the Gnawa heal those they believe to be possessed, using incense, music, and trance. But their practice is hardly of only local interest: the Gnawa have long participated in the world music market through collaborations with African-American jazz musicians and French recording artists. In this first book in English on Gnawa music and its global reach, author Deborah Kapchan explores how these collaborations transfigure racial and musical identities on both sides of the Atlantic. She also addresses how aesthetic styles associated with the sacred come to inhabit non-sacred contexts, and what new amalgams they produce. Her narrative details the fascinating intrinsic properties of trance, including details of enactment, the role of gesture and the body, and the use of the senses, and how they both construct authentic Gnawa identity and reconstruct historically determined relations of power. Traveling Spirit Masters is a captivating and elucidating demonstration of how and why trance—and indeed all sacred music—is fast becoming a transnational sensation.