In this dense, deeply researched, and edifying volume, Medani takes on the vexed question of how Islamist political movements use informal financial networks in recruiting and sustaining their members. He draws on an unusual and remarkably fruitful comparison of the Islamists of Egypt, Somalia, and Sudan, starting in the 1980s. That decade witnessed the rapid expansion of migrant labor to the Gulf and the parallel growth of remittances sent home by migrant workers. The elaborate informal mechanisms for transferring money were shaped by, and in turn reinforced, networks of clan, tribal, and religious affiliation. New private banks and other financial institutions helped strengthen an Islamist bourgeoisie in Egypt and an Islamist military elite in Sudan. In the 1990s, an economic downturn in the region limited the capacity of states to manage the economy and restrain local militant mobilization. Somalia’s state succumbed altogether; the regime in Egypt cracked down, pushing many moderate Islamists into the waiting arms of more militant groups; and Sudan staggered under the international sanctions imposed on its Islamist government. Medani is particularly acute in describing the complexity of local politics in these countries. The utility of regional identities, clan links, and religious ties varied with fluctuations not only of state policy but also of global business cycles.