The history of Islamic thought is a well-told tale, by both Muslim and Western scholars. This brief book thus offers little new. But it is a more than serviceable introduction for English-speaking readers who want to learn about (or need a refresher on) a wide variety of subjects, including the historical antecedents of the modern-day Salafists, the significance of the medieval Islamic scholar Ibn Tay-miyyah, the origins of the Wahhabis, and the basis of the concept of velayat-e faqih (rule by the jurisprudent), which the Iranian revolutionary Ruhollah Khomeini used to justify the clergy’s seizure of political power in Iran. Morrissey obviously enjoys the history of ideas—in his words, Islamic thought is an “intrinsically fascinating” subject—including recondite debates about the nature of God or the relationship between reason and revelation. Many knowledgeable readers will quibble with an occasional emphasis or interpretation, but on the whole, Morrissey does a good job tracing this diverse canon in clear, genial prose.