An essential aspect of what is now called the Islamic Revival, the cassette sermon can be heard in most Middle Eastern cities, punctuating the daily routines of many men and women. Charles Hirschkind shows how these tapes provide the means by which Islamic ethical traditions recalibrate to a modern political and technological order--to its noise and forms of pleasure and boredom, but also to its political incitements and call for citizen participation. Focusing on Cairo's popular neighborhoods, Hirschkind highlights the pivotal role sermon tapes now play in an expanding arena of Islamic argumentation and debate--what he calls an "Islamic counterpublic"--that connects Islamic traditions of ethical discipline to practices of deliberation about the common good, the duties of Muslims as national citizens, and the challenges faced by Muslim communities across the globe. Contrary to the belief that these cassettes are a tool of militant indoctrination, Hirschkind argues that sermon tapes are an instrument of ethical self-improvement and a vehicle for honing the affects of pious living.