Demonstrating the central role of third/ninth century hadîth scholars in the articulation of Sunnî Islam, this book bases its findings largely upon the analysis of multiple biographical dictionaries, such as al-Dhahabî’s Tadhkirat al-huffâz, Ibn Sa"d’s Kitâb al-tabaqât al-kabîr, and collections of the critical comments of Ibn Maʿîn and Ibn Hanbal. Part I establishes conceptual and historical frameworks for the study of Sunnî hadîth scholarship. Part II examines in detail the three foundational principles of Sunnî Islam: 1) the collective probity of the sahâba, 2) the discipline of hadîth-transmitter criticism, and 3) a historical vision of the authoritative channels by which hadîth traversed the two centuries between the life of the Prophet Muhammad and the first major hadîth books.