In the summer of 1978, Musa al Sadr, the spiritual leader of the Muslim Shia sect in Lebanon, disappeared mysteriously while on a visit to Libya. As in the Shia myth of the "Hidden Imam," this modern-day Imam left his followers upholding his legacy and awaiting his return. Considered an outsider when he had arrived in Lebanon in 1959 from his native Iran, he gradually assumed the role of charismatic mullah, and was instrumental in transforming the Shia, a quiescent and downtrodden Islamic minority, into committed political activists. What sort of person was Musa al Sadr? What beliefs in the Shia doctrine did his life embody? Where did he fit into the tangle of Lebanon's warring factions? What was behind his disappearance? In this fascinating and compelling narrative, Fouad Ajami resurrects the Shia's neglected history, both distant and recent, and interweaves the life and work of Musa al Sadr with the larger strands of the Shia past.