Book excerpt: Salafism has received scrutiny as the one of the main ideological sources for extremist violence perpetrated by jihadi groups. There is a significant corpus of literature discussing transnational jihadi networks, especially after the 9/11 attacks in the United States. These discussions include the radicalization of Salafi thought by jihadi theoreticians and 'ulama. However, Salafism is not monolithic. It contains numerous streams, and an examination of these streams is crucial to understanding its influence on Muslim societies. Besides Salafi jihadisthose who sanction violencethere are two other broad trends in Salafism: quietist and activist. Quietist Salafis endorse an apolitical tradition and find political activism in any form unacceptable. Activist Salafis advocate peaceful political change. Each stream is led by 'ulama, seen as the preservers of Salafi traditions. The quietist and activist 'ulama are active participants in their communities. Studies of such clerics have tended to be country-specific, focusing on the influence and nature of Salafism and its dynamics in those countries. In Rethinking Salafism Raihan Ismail assesses the origins, interactions, and dynamics of the transnational networks of Salafi 'ulama in the region comprising Saudi Arabia, Egypt, and Kuwait, showing how quietist and activist 'ulama work across borders to preserve and promote what they see as "authentic" Salafism while taking domestic circumstances of the 'ulama into consideration. The book offers a reassessment of the quietist/activist dichotomy, arguing that this dichotomy does not apply to such aspects of Salafi thought as attitudes towards the Shi'a and social matters in Muslim societies.