<P>Throughout the Middle East, Islamist charities and social welfare organizations play a major role in addressing the socioeconomic needs of Muslim societies, independently of the state. Through case studies of Islamic medical clinics in Egypt, the Islamic Center Charity Society in Jordan, and the Islah Women's Charitable Society in Yemen, Janine A. Clark examines the structure and dynamics of moderate Islamic institutions and their social and political impact. Questioning the widespread assumption that such organizations primarily serve the poorer classes, Clark argues that these organizations in fact are run by and for the middle class. Rather than the vertical recruitment or mobilization of the poor that they are often presumed to promote, Islamic social institutions play an important role in strengthening social networks that bind middle-class professionals, volunteers, and clients. Ties of solidarity that develop along these horizontal lines foster the development of new social networks and the diffusion of new ideas.</P>