As the revered senior Shia cleric in a Shia-majority country, Sistani commands the loyalty of millions of faithful. With quiet authority, Sistani has tried from behind the scenes to steer Iraq through a series of existential crises since the U.S. invasion and fall of Saddam Hussein's regime in 2003.

Century International fellow Sajad Jiyad draws on new sources and hundreds of interviews during decades of fieldwork inside Iraq to argue that Sistani has redefined the role of the Shia clergy and created a model of indirect influence that starkly differs from Iran's approach of direct clerical rule.

Contenders have already begun positioning themselves to succeed Sistani, and Jiyad assesses the players and the complex selection process for Najaf's leadership.

Observers of Iraq and of Shia power will find God's Man in Iraq: The Life and Leadership of Grand Ayatollah Ali al-Sistani an incomparable appraisal of Sistani's legacy-and an invaluable guide to the perilous transition that will follow his tenure.