My dissertation will use understudied manuscript materials in Tashkent, Bukhara, and Samarkand, Uzbekistan, and in Istanbul, Turkey, to explore how medieval Muslim scholars constructed a uniquely Islamic theory of knowledge. This epistemology resulted in the unquestionable historical validity of the Qur'an and statements from the Prophet Muhammad. It is exemplified by the development of the testimonial concept "tawatur," which describes the transmission of a statement by a sufficient number of agents over time and space so as to preclude error and agreement on a lie, and guarantees knowledge for the recipient of the statement. For this research project, I will examine works of Islamic legal theory and theology for theoretical debates about tawatur, and Qur'an commentaries, histories, and belles-lettres for doctrinal applications of tawatur. This project will complement research I have undertaken in the past year at the Süleymaniye Library in Istanbul, Turkey, that aims to construct a more coherent picture of the intellectual relationships among medieval Muslim scholarly networks inside and outside of the region known as Transoxania (present-day Uzbekistan). My work on intellectual and scholarly networks will allow me to trace the development of tawatur as an epistemological concept, and to examine the influence of Transoxanian Islamic thought in more central Islamic areas such as Iran and Iraq. By utilizing my Arabic and Persian language abilities and experience in reading manuscripts, and by studying Transoxania within a framework that recognizes the area as geographically peripheral but intellectually central, I intend to begin to fill the gap that is pre-modern Transoxania created by Russian Studies and Middle Eastern Studies scholarship. Concurrently, my project will bring in novel approaches to epistemology and testimony from the field of philosophy, contributing to the development of an Islamic Studies conception of "verstehen."