This book is the first devoted to Hume’s conception of testimony. Hume is usually taken to be a reductionist with respect to testimony, with trust in others dependent on the evidence possessed by individuals concerning the reliability of texts or speakers. This account is taken from Hume’s essay on miracles in An Enquiry concerning Human Understanding. O’Brien, though, looks wider than the miracles essay, turning to what Hume says about testimony in the Treatise, the moral Enquiry, the History of England and his Essays. There are social aspects of testimonial exchanges that cannot be explained purely in terms of the assessment of the reliability of testifiers. Hume’s conception of testimony is integrated with his account of how history informs our knowledge of human nature, the relation between sympathy and belief and between pride and the conception we have of our selves, the role played by social factors in the judgment of intellectual virtue, and the importance Hume places on epistemic responsibility and the moral and personal dimensions of testimonial trust. It is not possible to focus on testimony without allowing other aspects of our nature into the frame and therefore turning also to consider sympathy, wisdom, history, morality, virtue, aesthetic judgment, the self, and character. O’Brien argues that Hume’s reliance on the social goes deep and that he should therefore be seen as an anti-reductionist with respect to testimony. Hume on Testimony will be of interest to researchers and advanced students working on Hume and on early modern and contemporary approaches to the epistemology of testimony.