This book explores the diverse ways digital technology is shaping how Muslims across vast territories relate to religious authorities in fulfilling spiritual, mystical, and legalistic agendas. From social networks to websites, essential elements of religious practices and authority now have representation online. Muslims, embracing the immediacy and general accessibility of the internet, are increasingly turning to cyberspace for advice and answers to important religious questions. Online environments often challenge traditional models of authority, however. One result is the rise of digitally literate religious scholars and authorities whose influence and impact go beyond traditional boundaries of imams, mullahs, and shaikhs. The book shows how online rhetoric and social media are being used to articulate religious faith by many different kinds of Muslim organizations and individuals, from Muslim comedians and women’s rights advocates to jihad-oriented groups, such as the “Islamic State” and al-Qaeda, which relied on strategic digital media policies to augment and justify their authority and draw recruits. Hashtag Islam makes clear that understanding CIEs is crucial for the holistic interpretation of authority in contemporary Islam.