In Europe and North America, networks tracing their origins back to the Muslim Brotherhood and other Islamist movements have rapidly evolved into multifunctional and richly funded organizations competing to become the major representatives of Western Muslim communities and government interlocutors. Some analysts and policy makers see these organizations as positive forces encouraging integration. Others cast them as modern-day Trojan horses, feigning moderation while radicalizing Western Muslims. Lorenzo Vidino brokers a third, more informed view. Drawing on more than a decade of research on political Islam in the West, he keenly analyzes a controversial movement that still remains relatively unknown. Conducting in-depth interviews on four continents and sourcing documents in ten languages, Vidino shares the history, methods, attitudes, and goals of the Western Brothers, as well as their phenomenal growth. He then flips the perspective, examining the response to these groups by Western governments, specifically those of Great Britain, Germany, and the United States. Highly informed and thoughtfully presented, Vidino's research sheds light on a critical juncture in Muslim-Western relations.