We citizens of the 21st century live in a world where division of epistemic labour rules. Most of what we know we learned from the spoken or written word of others, and we depend in endless practical ways on the technological fruits of the dispersed knowledge of others—of which we often know almost nothing—in virtually every moment of our lives. Interest has been growing in recent years amongst philosophers, in the issues in epistemology raised by this fact. One issue concerns (...) the depth and extent of our epistemic dependence on testimony, as we may label this broad epistemic source: Do we have any knowledge at all that is free of epistemic dependence on what we have learned from others? A related question is whether our entitlement to believe what we have learned from others can be explained without invoking any epistemic principles special to testimony. These questions concern, as it were, the macro-epistemology of testimony. In the present discussion I shall focus instead on the micro foundations. Testimony, in our broad sense, can occur through an extensive range of types of spoken and written means of purportedly factual communication, including telephone calls, e-mails and personal letters, lectures and radio broadcasts, newspapers, textbooks and encyclopaedias, personal diaries, and public records of all kinds. But the central paradigm—what started the whole communication thing off—is surely that of face-to-face spoken encounter, when one person tells something to another, thereby intending and hoping to share her knowledge with her audience. I begin by describing the speech act of telling, identifying what takes place in a felicitous act of telling. From the nature of the speech act of telling, we see precisely how it is that knowledge is, when all goes as it should, acquired from teller by trusting hearer, in such an act, and in acts of testimony more broadly. (shrink)