Testimony is a crucial source of knowledge: we are to a large extent reliant upon what others tell us. It has been the subject of much recent interest in epistemology, and this volume collects twelve original essays on the topic by some of the world's leading philosophers. It will be the starting point for future research in this fertile field. Contributors include Robert Audi, C. A. J. Coady, Elizabeth Fricker, Richard Fumerton, Sanford C. Goldberg, Peter Graham, Jennifer Lackey, Keith Lehrer, Richard Moran, Frederick F. Schmitt, Ernest Sosa, and James Van Cleve.