Two lead essays offer differing viewpoints: Donald K. Emmerson argues that Islamism is a useful term for a range of Muslim reform movements—very few of which advocate violence—while Daniel M. Varisco counters that the public specter of violence and terrorism by Islamists too often infects the public perceptions of Islam more generally. Twelve commentaries, written by Muslim and non-Muslim intellectuals, enrich the debate with differing insights and perspectives.